2014
Washington State K–12 Facilities Hazard Mitigation Plan
School Facilities and Organization Office of Superintendent of Public Instruction (OSPI) Prepared by:
Kenneth Goettel, Goettel and Associates, Inc. Robert Dengel, School Facilities and Organization
School Facilities and Organization Office of Superintendent of Public Instruction Gordon Beck, Director
OSPI provides equal access to all programs and services without discrimination based on sex, race, creed, religion, color, national origin, age, honorably discharged veteran or military status, sexual orientation including gender expression or identity, the presence of any sensory, mental, or physical disability, or the use of a trained dog guide or service animal by a person with a disability. Questions and complaints of alleged discrimination should be directed to the Equity and Civil Rights Director at (360) 725-6162 or P.O. Box 47200 Olympia, WA 98504-7200.
Table of Contents
Executive Summary ...... 9
Chapter One: Introduction ...... 11
1.1 What is a Hazard Mitigation Plan? ...... 11 1.2 Why is Hazard Mitigation Planning Important for Washington State, OSPI, and School Districts? . 12 1.3 Mitigation Planning: Key Concepts and Definitions ...... 14 1.4 The Mitigation Process...... 18 1.5 The Role of Benefit-Cost Analysis in Hazard Mitigation Planning ...... 20 1.6 Synopsis of Natural Hazards Affecting K–12 Facilities in Washington State ...... 21 Chapter Two: Community Profile ...... 23
2.1 Overview ...... 23 2.2 OSPI’s Mission and Responsibilities ...... 23 2.3 Washington State K–12 School Districts ...... 23 2.4 Washington State K–12 Students ...... 24 Chapter Three: Mitigation Planning Process ...... 30
3.1 Washington State K–12 Facilities Hazard Mitigation Plan: Overview ...... 30 3.2 Mitigation Planning Process Documentation ...... 32 Participants in the Planning Process ...... 32 Washington State K–12 Facilities Hazard Mitigation Plan Planning Team Meetings ...... 33 Survey Questionnaire ...... 34 Concerns about Consequences of Natural Hazard Events ...... 35 Goals for Addressing Risks for Schools ...... 36 Level of Threat from Different Hazards ...... 36 Concerns about Hazards of Differing Frequency and Severity ...... 37 Strategies for Addressing Risks for Schools ...... 38 Other Risk Reduction Strategies ...... 39 Chapter Four: Mission Statement Goals, Objectives, and Action Items ...... 40
4.1 Overview ...... 40 4.2 Mission Statement ...... 41 4.3 Mitigation Plan Goals and Objectives ...... 41 4.4 Mitigation Planning and Implementation Priorities ...... 43 4.5 Washington State K–12 Facilities Hazard Mitigation Plan Action Items ...... 43 Chapter Five: Mitigation Plan Implementation and Updating ...... 45
5.1 Overview ...... 45 5.2 Coordinating Body ...... 45 5.3 Implementation and Integration into Ongoing Programs, Policies, and Practices ...... 45 5.4 Periodic Evaluation and Updating ...... 46 Chapter Six: Natural Hazards Risk ...... 48
6.1 Overview ...... 48 Hazard ...... 49 Exposure ...... 49 Risk ...... 49 6.2 Natural Hazards Overview ...... 50 6.3 Natural Hazards Risk Assessment, a Three-Step Process ...... 51 6.4 Evaluating Acceptable Risk ...... 56 6.5 Establishing Mitigation Priorities ...... 58 6.6 Implementing Mitigation Measures ...... 61 Chapter Seven: Earthquakes ...... 64
7.1 Introduction ...... 64 7.2 Washington Earthquakes ...... 64 7.3 Earthquake Concepts for Risk Assessments ...... 74 Earthquake Magnitudes ...... 74 Intensity of Ground Shaking...... 75 7.4 Earthquake Hazard Maps ...... 76 7.5 Site Class: Soil and Rock Types ...... 83 7.6 Ground Failures and Other Aspects of Seismic Hazards ...... 85 Surface Rupture ...... 85 Subsidence or Uplift ...... 85 Liquefaction, Settlement, and Lateral Spreading ...... 85 Landslides ...... 86 Dam, Levee, and Reservoir Failures ...... 86 Tsunamis and Seiches ...... 86 7.7 Scenario Earthquake Loss Estimates for K–12 Facilities in Washington ...... 87 Scenario Earthquakes...... 87 HAZUS Loss Estimates for Scenario Earthquakes ...... 88 7.8 Seismic Hazard and Risk Assessments at the Campus- and Building-Levels...... 96 Campus-Level Seismic Hazard and Risk Assessments: Main Steps ...... 96 Building-Level Seismic Hazard and Rick Assessments: Main Steps...... 96 7.9 Earthquake Hazard Mitigation Measures for K–12 Facilities ...... 97 Typical Seismic Mitigation Measures ...... 97 Seismic Retrofit Costs for K–12 Facilities ...... 98 Seismic Retrofits for K–12 Facilities: Performance Objectives ...... 99 Chapter Eight: Tsunamis ...... 102
8.1 Overview ...... 102 8.2 Tsunami Sources ...... 104 8.3 Historical Tsunamis Affecting Washington State ...... 107 Local Tsunamis ...... 107 Distant Tsunamis ...... 107 Effect of Global Climate Change and Sea Level Rise ...... 107 8.4 Tsunami Hazard Analysis and Mapping ...... 108 8.5 Tsunami Hazard and Risk Assessment for K–12 Facilities ...... 126 8.6 Tsunami Loss Estimates ...... 135 Distant Tsunami Events ...... 136 Local Tsunami Events: Puget Sound Earthquakes...... 137 M9.0 Earthquakes on the Cascadia Subduction Zone ...... 137 8.7 Tsunami Mitigation Measures ...... 139 Evacuation Planning ...... 139 Vertical Evacuation ...... 140 Other Tsunami Mitigation Measures ...... 140 Chapter Nine: Volcanic Hazards ...... 142
9.1 Overview ...... 142 9.2 Volcanic Hazard Types ...... 144 Proximal Volcanic Hazards (Effects near Volcanic Source Only) ...... 145 Distal Volcanic Hazards (Effects at Considerable Distances from Volcanic Source) ...... 145 Volcanic Event Warning Times ...... 146 9.3 Volcanic Hazards for K–12 Facilities ...... 146 Volcanic Hazard Maps ...... 147 Ash Falls ...... 158 9.4 Volcanic Hazards Risk Assessment ...... 160 9.5 Mitigation of Volcanic Hazards ...... 171 Volcano Monitoring and Volcano Activity Alerts ...... 171 Know how to respond to a lahar warning...... 173 Volcanic Hazard Mitigation Measures ...... 173 Chapter Ten: Floods ...... 175
10.1 Introduction ...... 175 10.2 Washington State Floods Overview ...... 177 10.3 FEMA-Mapped Floodplains ...... 180 10.4 Campuses within FEMA-Mapped Floodplains ...... 185 10.5 Flood Hazard Data ...... 189 10.6 Flood Hazards and Flood Risk Outside of Mapped Floodplains ...... 190 Dam, Reservoir, and Levee Failures ...... 191 Dams ...... 191 Reservoirs ...... 193 Levees ...... 193 Risk Assessments for Dam, Reservoir, and Levee Failures ...... 193 10.7 Flood Scenario Loss Estimates ...... 194 Methods ...... 194 Statewide 100-Year Flood Scenario Results ...... 194 10.8 Flood Risk Assessments at the District, Campus, and Building Levels ...... 196 10.9 Flood Mitigation Projects ...... 198 Chapter Eleven: Wildland/Urban Interface Fires ...... 200
11.1 Overview ...... 200 11.2 Wildland/Urban Interface Fires ...... 201 11.3 Historical Fire Data for Washington State ...... 202 11.4 Wildland and Wildland/Urban Fire Hazard Mapping and Hazard Assessment ...... 205 11.5 Wildland/Urban Interface Fire Hazard and Risk ...... 209 11.6 Wildland/Urban Fires: Potential Loss Estimates for K–12 Facilities ...... 224 11.7 Mitigation Strategies for Wildland/Urban Interface Fires ...... 225 Chapter Twelve: Landslides ...... 227
12.1 Landslide Overview and Definitions ...... 227 12.2 Landslide Hazard Mapping and Hazard Assessment ...... 232 12.3 Landslide Hazard and Risk Assessments for K–12 Facilities ...... 237 12.4 Mitigation of Landslide Risk ...... 245 Chapter Thirteen: Other Natural Hazards ...... 246
13.1 Avalanches ...... 246 13.2 Drought ...... 247 13.3 Severe Weather ...... 248 High Winds ...... 249 Snow and Ice Storms ...... 250 Thunderstorms and Hail Storms ...... 250 Tornadoes ...... 250 Extreme Temperatures ...... 251 Mitigation Measures for Severe Weather ...... 252 13.4 Climate Change ...... 252 13.5 Subsidence ...... 253 Appendix One: Scenario Earthquake Results ...... 254
Appendix Two: References ...... 271
List of Tables
Table 1.1 Common Mitigation Projects for K–12 Facilities ...... 17
Table 2.1 Washington State K–12 Student Headcount Enrollment 2013 School Year ...... 25
Table 2.2 English Proficiency...... 25
Table 2.3 Students from Economically Disadvantaged Homes ...... 26
Table 2.4 Districts and Other K–12 Related Institutions by Student Enrollment ...... 26
Table 2.5 2013 School Year Student Headcount Enrollment by District ...... 27
Table 3.1 Main Steps in Mitigation Planning and Implementation Process ...... 31
Table 3.2 Planning Team Members ...... 32
Table 3.3 Survey Responses by County ...... 34
Table 4.1 Multi-Hazard Mitigation Action Items ...... 44
Table 6.1 Probabilistic Risk Table ...... 57
Table 7.1 Largest Recorded Earthquakes ...... 64
Table 7.2 USGS Mapped Faults in the Puget Sound Area ...... 70
Table 7.3 USGS Mapped Faults in the Walla Walla Area ...... 72
Table 7.4 Earthquake Ground Motions with a Two Percent Chance of Being Exceeded in 50 Years ...... 83
Table 7.5 International Building Code Site Class Technical Definitions ...... 84
Table 7.6 Scenario Earthquakes ...... 88
Table 7.7 Summary of HAZUS Scenario Earthquake Results: K–12 Facilities Statewide ...... 91
Table 7.8 Cascadia Subduction Zone Interface M9.0 Scenario...... 93
Table 7.9 Expected Average Annual Earthquake Losses ...... 95
Table 7.10 Possible Seismic Retrofit Performance Objectives ...... 100
Table 8.1 Tsunami Risk Categories ...... 128
Table 8.2 Schools within Mapped Tsunami Inundation Zones ...... 129
Table 8.3 Schools within Five Miles of Coast and Elevation Below 30 Feet ...... 130 Table 8.4 Schools within Five Miles of Coast and Elevation Between 30 and 50 Feet ...... 132
Table 8.5 Schools within Five Miles of Coast and Elevation Between 50 and 100 Feet ...... 133
Table 8.6 Tsunami Damage and Death Estimates for Tsunamis with Schools in Session ...... 139
Table 9.1 Active Volcanoes in Washington ...... 142
Table 9.2 USGS Volcano Threat Potential ...... 144
Table 9.3 Volcano Websites ...... 144
Table 9.4 USGS Mapped Volcanic Hazard Zones ...... 161
Table 9.5 Volcanic Hazard Levels ...... 162 Table 9.6 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Rainer (Very High Hazard) ...... 163
Table 9.7 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Rainer (High Hazard) ...... 164
Table 9.8 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Rainer (Moderate Hazard) ...... 165
Table 9.9 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Rainer (Moderate Hazard) ...... 166
Table 9.10 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Rainer (Very Low Hazard) ...... 167
Table 9.11 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Baker or Glacier Peak ...... 168
Table 9.12 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Baker and Glacier Peak ...... 169
Table 9.13 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Adams ...... 170
Table 10.1 High Risk Areas ...... 183
Table 10.2 High Risk Coastal Areas ...... 184
Table 10.3 Moderate to Low Risk Areas ...... 184
Table 10.4 Undetermined Risk Areas ...... 184
Table 10.5 Campuses within FEMA Mapped Flood Plains ...... 186 Table 10.6 Flood Hazard Data Example Chehalis River at Confluence with Skookumchuck River ...... 189
Table 10.7 Aggregated Values for 169 Campuses ...... 195
Table 10.8 FEMA Flood Depth-Damage Functions for Schools ...... 195
Table 10.9 Scenario Loss Estimates: Hypothetical Statewide 100-Year Flood for the 169 Campuses within FEMA-Mapped Floodplains ...... 196
Table 11.1 2011 Washington Wildland Fire Data – Federal and State Agencies Only ...... 205
Table 11.2 Wildland/Urban Interface Communities Identified by DNR ...... 211
Table 11.3 USGS Landfire Return Periods Less Than 50 Years K–12 Facilities Not Within DNR Wildland/Urban Interface Communities ...... 216
Table 11.4 Potential Losses for Wildland/Urban Interface Fires Affecting K–12 Campuses ...... 225
Table 12.1 Preliminary Landslide Hazard and Risk Assessment ...... 238
List of Figures
Figure 1.1 Hazard and Exposure Combine to Produce Risk ...... 15
Figure 1.2 Mitigation Projects Reduce Risk ...... 18
Figure 1.3 Hazard Mitigation Planning Process Flowchart ...... 19
Figure 2.1 Washington State School Districts ...... 24
Figure 3.1 Main Steps in the Mitigation Planning and Implementation Process ...... 30
Figure 3.2 Survey Responses by County ...... 35
Figure 3.3 Concerns about Natural Hazard Events ...... 35
Figure 3.4 Risk Reduction Goals ...... 36
Figure 3.5 Perceived Threat by Hazard Type ...... 37
Figure 3.6 Concerns about Hazard Frequency and Damage ...... 38
Figure 3.7 Risk Reduction Strategies...... 39
Figure 6.1 Hazard and Exposure Combine to Produce Risk ...... 49
Figure 6.2 ICOS Hazard and Risk Assessment Approach ...... 55
Figure 6.3 The Hazard Mitigation Planning Process Flowchart ...... 61
Figure 7.1 Epicenters of Historic Earthquakes in Washington with Magnitudes of 3.0 or Higher ...... 65
Figure 7.2 Cascadia Subduction Zone ...... 67
Figure 7.3 Time History of Cascadia Subduction Zone Interface Earthquakes ...... 68
Figure 7.4 USGS Mapped Crustal Faults in the Puget Sound Area ...... 69
Figure 7.5 USGS Mapped Faults in the Walla Walla Area ...... 71
Figure 7.6 Faults and Seismogenic Folds in Washington Known or Suspected to be Active ...... 73
Figure 7.7 2008 USGS Seismic Hazard Map: Washington State PGA value (percent g) with a Two Percent Chance of Exceedance in 50 years ...... 78
Figure 7.8 2008 USGS Seismic Hazard Map: Washington State PGA value (percent g) with a Ten percent Chance of Exceedance in 50 years ...... 79 Figure 7.9 2008 USGS Seismic Hazard Map: Puget Sound Area PGA value (percent g) with a Two percent Chance of Exceedance in 50 years ...... 80
Figure 7.10 2008 USGS Seismic Hazard Map: Puget Sound Area PGA value (percent g) with a Ten percent Chance of Exceedance in 50 years ...... 81
Figure 7.11 Seismic Hazard Curve Example ...... 82
Figure 7.12 Cascadia Subduction Zone Interface M9.0 Scenario ...... 94
Figure 8.1 Earthquake-Generated Tsunamis ...... 102
Figure 8.2 Tsunami Surges in Hilo, Hawaii from M9.5 1960 Chile Earthquake ...... 103
Figure 8.3 Complete Destruction: March 2011 Tohoku Tsunami, Japan ...... 104
Figure 8.4 Tsunami Travel Times: M9.2 1964 Prince William Sound Alaska Earthquake. (Travel Time Contours are Hours) ...... 105
Figure 8.5 Tsunami Zones: Mapped and Unmapped ...... 110
Figure 8.6 Example Tsunami Evacuation Map/Brochure: Aberdeen – Hoquiam11 ...... 111
Figure 8.7 Tsunami Inundation Map: Overall ...... 113
Figure 8.8 Tsunami Inundation Map: Ferndale School District ...... 114
Figure 8.9 Tsunami Inundation Map: Burlington Edison School District ...... 115
Figure 8.10 Tsunami Inundation Map: La Conner School District ...... 116
Figure 8.11 Tsunami Inundation Map: Seattle School District ...... 117
Figure 8.12 Tsunami Inundation Map: North Beach School District ...... 118
Figure 8.13 Tsunami Inundation Map: Ocosta School District ...... 119
Figure 8.14 Tsunami Inundation Map: Ocean Beach School District ...... 120
Figure 8.15 Tsunami Inundation Map: Tacoma and Vicinity ...... 121
Figure 8.16 Tsunami Inundation Map: Cape Flattery School District ...... 122
Figure 8.17 Tsunami Inundation Map: Taholah School District ...... 123
Figure 8.18 Tsunami Inundation Map: Hoquiam – Aberdeen School Districts ...... 124
Figure 8.19 Tsunami Inundation Map: Raymond – South Bend School Districts ...... 125
Figure 9.1 Washington Volcanoes and Mount Hood ...... 143 Figure 9.2 Volcanic Hazard Map: Overall ...... 148
Figure 9.3 Mount Rainier Volcanic Hazards Map ...... 149
Figure 9.3A Mount Rainier Volcanic Hazards Map: Northwest Area Close-Up ...... 150
Figure 9.3B Mount Rainier Volcanic Hazards Map: West Area Close-Up ...... 151
Figure 9.3C Mount Rainier Volcanic Hazards Map: Southwest Area Close-Up ...... 152
Figure 9.4 Mount Baker and Glacier Peak Lahar Map ...... 153
Figure 9.4A Mount Baker and Glacier Peak Lateral Blast Zone Map ...... 154
Figure 9.5 Mount Adams Volcanic Hazards Map ...... 155
Figure 9.6 Mount St. Helens Lahar Map ...... 156
Figure 9.7 Mount Hood Volcanic Hazards Map ...... 157
Figure 9.8 USGS Ash Fall Probabilistic Maps ...... 159
Figure 9.14 Volcanic Alert Levels for People on the Ground ...... 172
Figure 10.1 Chehalis River Flood in Centralia, Washington–December 2007 ...... 175
Figure 10.2 Storm Surge Effects ...... 176
Figure 10.3 Frequency of Presidential Disaster Declarations for Flooding ...... 178
Figure 10.4 100-Year, 24-Hour Precipitation ...... 179
Figure 10.5 FEMA-Mapped Floodplains in Washington State ...... 181
Figure 10.6 FEMA Firmette for A.J. West Elementary School in Aberdeen ...... 182
Figure 10.7 Dams in the Columbia River Watershed ...... 192
Figure 11.1 Pateros School Fire (July, 2014) ...... 203
Figure 11.2 Washington State Wildland Fire Statistics 2001-2011 Federal and State Agencies Only ...... 204
Figure 11.3 Wildland/Urban Interface Communities Identified by Washington Department of Natural Resources ...... 206
Figure 11.4 Washington Wildland/Urban Interface High Risk Communities and Statewide Assessment High and Moderate Risk Areas ...... 207
Figure 11.5 United States Geological Survey Landfire Return Period Map ...... 207 Figure 12.1 Landslide Nomenclature ...... 227
Figure 12.2 Major Types of Landslides ...... 228
Figure 12.3 Oso Landslide (March 22, 2014) ...... 229
Figure 12.4 Oso Landslide Vicinity (Before Landslide) ...... 230
Figure 12.5 Rolling Bay, Bainbridge Island 1997 ...... 231
Figure 12.6 Road 170 Near Basin City 2006 ...... 231
Figure 12.7 Highway 410 Near Town of Nile 2009 ...... 232
Figure 12.8 DNR Mapped Landslides ...... 234
Figure 12.9 Landslide Incidence and Potential ...... 235
Figure 12.10 Department of Natural Resources – Landslide Potential Map ...... 236
Figure 13.1 Elevations Above 2,000 Feet in Washington ...... 246
Figure 13.2 Drought Susceptibility for Washington State ...... 248
Figure 13.3 Counties Most Vulnerable to High Winds ...... 249
Figure 13.4 Washington State Tornadoes Since 1950 ...... 251
Executive Summary The Office of Superintendent of Public Instruction (OSPI) has completed the Washington State K–12 Facilities Hazard Mitigation Plan which was funded by a Federal Emergency Management Agency (FEMA) grant. This plan is the first in the nation to focus specifically on K–12 facilities statewide. The overall purpose is to reduce the impact of future natural hazard disasters on K–12 schools in Washington State. The mission statement for the plan is: Proactively facilitate and support statewide resources and programs that assist school districts in making K–12 schools in Washington State more disaster resistant and disaster resilient. The mitigation plan is the first step in a three-part process to reduce the risks from natural hazards to K–12 facilities in Washington State. It provides a statewide risk assessment of six natural hazards that pose the greatest threat to K–12 facilities, including earthquakes, tsunamis, volcanic events, floods, wildland fires, and landslides. The plan also identifies which campuses face significant risk from one or more of these hazards. The risk assessment is based on the best available natural hazard information currently available from the United States Geological Survey, FEMA, the Department of Natural Resources, and the Department of Ecology, etc. Only a fraction of K–12 facilities in Washington are at significant risk from the six hazards, although, the risk is high for several of those facilities. Earthquakes pose significant risk to many of Washington’s K–12 facilities. Even though there is some level of risk statewide, most of the facilities with high earthquake risk are located in western Washington. The mitigation plan also addresses (in lesser detail) natural hazards which pose lower risk to K–12 facilities, or risks to only a small number of K–12 facilities, including avalanches, drought, severe weather, and others. The second step in OSPI’s mitigation planning process is the development of a toolkit to facilitate more detailed risk assessments at the district, campus, and building-level, and to help districts develop their own district-specific mitigation plans. The toolkit identifies local data necessary to refine statewide risk assessments so districts can make meaningful risk assessments and develop mitigation plans with minimum effort. The goal of this second step is to identify specific campuses, or individual K–12 buildings, where risk from one or more natural hazards is high enough to warrant mitigation projects. Twenty-eight school districts have volunteered to develop their own mitigation plan through a pilot approach. That pilot includes a planning toolkit that OSPI has developed with funds received from the FEMA planning grant. Based on a clear understanding of existing natural hazards risks in Washington, OSPI will help school districts allocate resources efficiently by identifying which facilities will benefit most from pro-active mitigation measures that reduce casualties, damages, and economic losses in future disasters. The third step is to facilitate and provide support for school districts to obtain funding to implement their highest priority mitigation projects, especially through FEMA grants. This step includes additional toolkit materials to guide the completion of FEMA grant applications. It includes guidance and templates for benefit-cost analyses which are a prerequisite for almost all FEMA mitigation grants.
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Completely eliminating the risk to K–12 schools in Washington State from future natural disasters is not technologically possible or economically feasible. However, substantially reducing the negative impacts of future disasters to K–12 schools is achievable with ongoing implementation of risk reduction measures. The Washington State K–12 Facilities Hazard Mitigation Plan focuses more narrowly on K–12 schools than the Washington State Enhanced Hazard Mitigation Plan that explains the impact of disasters for the state at large. Given the focus on K–12 schools, the Washington State K–12 Facilities Hazard Mitigation Plan has a much greater level of detail than is possible in the broader Washington State Enhanced Hazard Mitigation Plan. Only by having a clear understanding of risks posed by natural hazards can OSPI effectively help school districts mitigate risk posed by natural hazards to K–12 facilities in Washington State. This mitigation plan provides a clear means to evaluate and assist school districts to address these risks by focusing on the highest priority projects first to save the most lives and avoid the most damage in future disasters.
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Chapter One: Introduction
1.1 What is a Hazard Mitigation Plan? Washington State is subject to many natural hazards that pose significant risks to people and to the environment of buildings and infrastructure. Natural hazard disasters result in damages, economic losses, and potential deaths and injuries. The natural hazards which pose the most risk to Washington State include earthquakes, tsunamis, floods, wildland/urban interface fires, volcanic events, and landslides. There are also other natural hazards that pose less severe, or more localized risks, such as avalanches, severe weather, drought, etc. It is widely recognized that many K–12 facilities in Washington State are at risk from one or more natural hazards. However, detailed information about the risk that school campuses are subject to from specific natural hazards and which campuses face the most severe risks, is not readily available. Without that information, it is impossible to prioritize measures to reduce risk in an effective manner. The overall purpose of the Washington State K–12 Facilities Hazard Mitigation Plan is to reduce the impacts of future natural hazard disasters on K–12 schools in Washington State. It is the first mitigation plan in the nation to focus specifically on K–12 facilities statewide. The mission statement for this plan is: Proactively facilitate and support statewide resources and programs that assist school districts in making K–12 schools in Washington State more disaster resistant and disaster resilient.
Completely eliminating risk to K–12 schools in Washington State from future natural disasters is neither technologically possible nor economically feasible. However, substantially reducing the negative impacts of future disasters is achievable with ongoing implementation of risk reduction measures. The main elements of hazard mitigation plans for natural hazards include: Providing a rigorous and understandable summary of the natural hazards that pose significant risks to the built environment including: o Identifying which locations are subject to which hazards. o Estimating the probabilities that hazard events will occur and how severe the damages, economic losses, and casualties will be. o Developing cost-effective, carefully-prioritized measures to reduce risk to facilities that have an unacceptably high level of risk from one or more natural hazards. That is, a hazard mitigation plan provides a “road-map” to guide actions that will reduce the risks from natural hazard disasters to the greatest extent practicable.
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OSPI’s hazard mitigation planning effort has three main phases: First, completing the Washington State K–12 Facilities Hazard Mitigation Plan that provides a statewide overview and lays a foundation for the second phase below. Second, supporting the development of hazard mitigation plans for individual school districts. This includes more detailed risk assessments than are possible in the Washington State K–12 Facilities Hazard Mitigation Plan. This second phase of the planning effort includes: o Developing a toolkit, templates, and guidance to facilitate school districts to create district-specific hazard mitigation plans with minimum effort and resources expended. o Conducting workshops to provide technical support for the 28 school district planning partners which are creating district-specific hazard mitigation plans under OSPI’s mitigation planning effort. Third, maximizing the potential for school districts to obtain mitigation grants from the Federal Emergency Management Agency (FEMA). This phase includes raising district awareness of FEMA grant programs and their requirements; providing much of the hazard, vulnerability, and risk assessments necessary to support successful FEMA grant applications; and completing at least ten benefit-cost analyses of high-priority mitigation projects created by districts. The Washington State K–12 Facilities Hazard Mitigation Plan builds upon, and is consistent with, the Washington State Enhanced Hazard Mitigation Plan. The Washington State Enhanced Hazard Mitigation Plan was updated in 2013, and it reviews each of the natural hazards that pose significant risk to people and built environments of Washington. The state mitigation plan identifies hazard mitigation goals, objectives, and actions that will prevent or reduce damages, deaths and injuries in future disaster events that affect Washington. The perspective of the state mitigation plan is necessarily broad and covers the entire state; although, the emphasis is on state-owned facilities. The Washington State K–12 Facilities Hazard Mitigation Plan focuses more narrowly on K–12 schools. It has a much greater level of detail than is possible in the broader Washington State Enhanced Hazard Mitigation Plan. Similarly, district-specific mitigation plans draw on both the Washington State Enhanced Hazard Mitigation Plan and the Washington State K–12 Facilities Hazard Mitigation Plan. District specific plans have more detailed hazard and vulnerability analyses for school facilities in each district including district specific priorities for mitigation goals, objectives, and action items.
1.2 Why is Hazard Mitigation Planning Important for Washington State, OSPI, and School Districts? Natural hazard disaster events will continue to occur in Washington State and affect communities and schools. It is not possible to prevent natural hazard events such as an earthquake, a tsunami, a volcanic eruption, or a flood from occurring, but the negative
Page | 12 impacts of event damages, other economic losses, deaths, and injuries can be avoided or substantially reduced by implementation of pragmatic, effective mitigation measures. Mitigation simply means actions that reduce the potential for negative impacts from future disasters. That is, mitigation actions reduce future damages, losses, and casualties. Hazard mitigation planning will help OSPI and school districts deal with natural hazards realistically and rationally. Mitigation planning by OSPI and school districts will identify specific schools where the level of risk from one or more hazards may be unacceptably high and help to find cost effective ways to reduce such risk. Effective mitigation planning strikes a pragmatic middle ground between unwisely ignoring the potential for major hazard events on one hand and unnecessarily overreacting to the potential for disasters on the other hand. That is, an effective mitigation plan identifies high risk facilities with an unacceptable level of risk and guides efforts to reduce risk. In this way, a robust hazard mitigation plan helps to ensure that the limited resources available for risk reduction are directed effectively to achieve the maximum possible reductions in risk. This minimizes the potential for future damages, economic losses, and casualties. Mitigation grants from FEMA may be an important source of funding for school districts to implement high-priority mitigation measures for natural hazards. A local government entity applying for a FEMA mitigation grant must have a FEMA-approved local hazard mitigation plan. A school district can meet this FEMA requirement in two ways: 1) having a FEMA-approved district mitigation plan or 2) participating in the development of a local mitigation plan by a city or county. There are several advantages for a school district to have its own FEMA-approved hazard mitigation plan: A mitigation planning process that assesses hazards that pose risk to district facilities and identifies the campuses or buildings with the highest risk. This helps a district to focus on mitigation measures that will reduce future damages, losses, and casualties to the greatest extent. That is, it will prioritize mitigation measures in the most effective manner. More detailed, district-specific hazard and risk information that will be able to support a district’s FEMA grant application much more effectively than the broader, less-focused information in a city or county hazard mitigation plan. The ability for a district with its own FEMA-approved hazard mitigation plan to apply directly to FEMA for funding, rather than having to compete with other possible mitigation projects in a city or county. The opportunity for a district with its own FEMA-approved plan to receive grant management funds that are included with many FEMA grants. The Washington State K–12 Facilities Hazard Mitigation Plan and the other materials developed in the OSPI mitigation planning process (toolkits, templates, and guidance to school districts) are specifically designed to support district efforts to obtain FEMA mitigation grants.
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The Washington State K–12 Facilities Hazard Mitigation Plan has helped OSPI gather the data necessary for school districts to compete successfully for future FEMA funding of mitigation projects. FEMA requires that all FEMA-funded hazard mitigation projects are “cost-effective” (i.e., the benefits of a project must exceed the costs). Therefore, benefit-cost analysis is an important component of hazard mitigation planning, not only to meet FEMA requirements, but also to help evaluate and prioritize potential hazard mitigation projects. This is true regardless if funding is from FEMA, state or local government, or from private sources.
1.3 Mitigation Planning: Key Concepts and Definitions The central concept of hazard mitigation planning is that mitigation reduces risks from natural hazards. The essence of hazard mitigation planning is to identify high risk locations and to evaluate ways to mitigate (reduce) the impacts of future disasters on these high risk locations/situations. There are four key concepts that govern hazard mitigation planning: hazard, exposure, risk, and mitigation. Each of these key concepts is addressed in turn. “Hazard” refers to natural or human-caused events that may cause damages, losses or casualties, for example earthquakes, tsunamis, and floods. Hazards are characterized by their frequency and severity and by the geographic area affected. Each hazard is characterized by appropriate parameters for the specific hazard. For example, floods are characterized by the frequency, flood depth, and flood velocity. Earthquakes are characterized by the frequency of occurrence and the intensity of earthquake ground motions. A hazard event does not necessarily result in negative impacts on a community. For example, a flood-prone parcel may experience several shallow floods per year with several feet of water expected in a 50-year flood event. However, if the parcel is natural wetlands with no buildings or infrastructure, there is no risk. That is, there is no threat to people or the built environment, and the frequent flooding of this parcel does not have any negative impacts on the community. In fact in this case, the frequent flooding (that is, the high hazard) may be beneficial environmentally by providing wildlife habitat and recreational opportunities. Hazards alone do not produce risk to people and property. Risk occurs only when there are vulnerable populations and properties exposed to the hazard. For school districts, a given hazard is important only when it poses significant threats to school facilities, students, and staff. Analysis of hazards is inherently probabilistic. It is not possible to predict when most hazard events will occur, but it is possible to estimate the probability of a hazard event occurring in any given year or over any given time period, such as the next 30 years. For example, a 100-year flood does not mean that such floods happen at one-hundred year intervals. It means, rather than the annual probability of such a flood occurring, there is a one percent probability per year and an average of once per 100 years. However, a given location may experience several 100-year flood events within a few years or go much longer than 100 years without experiencing a single such flood. “Exposure” is the quantity, value, and vulnerability of the built environment (inventory of people, buildings, and infrastructure) in a particular location subject to one or more hazards. Inventory is described by the number, size, type, use, and occupancy of buildings and by the infrastructure present. Infrastructure includes roads and other transportation systems, utilities
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(potable water, wastewater, natural gas, and electric power), telecommunications systems and so on. Inventory varies markedly in its importance to a community and thus varies markedly in its importance for hazard mitigation planning. Some types of facilities, “critical facilities,” are especially important to a community, particularly during disaster situations. Examples of critical facilities include police and fire stations, hospitals, schools, emergency shelters, 911 centers, etc. Critical facilities may also include important utility and transportation infrastructure. For hazard mitigation planning, inventory must be characterized not only by the quantity and value of buildings or infrastructure present, but also by its vulnerability to each hazard under evaluation. For example, a given facility may or may not be particularly vulnerable to flood damages or earthquake damages depending on the details of its design and construction. Depending on the hazard, different measures of the vulnerability of buildings and infrastructure are often used. For school districts, exposure is the quantity and value of school facilities exposed to a given natural hazard. Buildings with higher occupancy, higher value, higher importance to the functioning of the district or buildings with a higher vulnerability to a given hazard have more “exposure” than buildings with lesser occupancy, value, importance or vulnerability. “Risk “is defined as the threat to people and the built environment posed by the hazards being considered. Risk is the potential for damages, losses, and casualties arising from the impact of hazards on the built environment. The level of risk at a given location, building, or facility depends on the combination of hazard and exposure as shown in Figure 1.1.
Figure 1.1 Hazard and Exposure Combine to Produce Risk
Another way to consider risk, is that it is the combination of the frequency of hazard events and the severity of the consequences if the hazard event does occur. Risk is best expressed quantitatively in dollars (estimates of potential damages and other economic losses) and in terms of casualties (numbers of deaths and injuries). A disaster event happens when a hazard event is combined with vulnerable inventory (that is when a hazard event strikes vulnerable inventory exposed to the hazard). The highest risk in a school district occurs in high hazard areas (frequent and/or severe hazard events) with a large inventory of important, vulnerable buildings.
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However, high risk can also occur in only moderate or even low hazard areas if there is a large inventory of highly vulnerable inventory exposed to the hazard. For example, an extremely vulnerable unreinforced masonry school building with a high occupancy may be very high risk, even in moderate to low seismic hazard locations in Washington. Conversely, a high hazard area can have relatively low risk if the inventory is resistant to damages (e.g. elevated to protect against flooding or strengthened to minimize earthquake damages). For mitigation planning, it is very important to understand that infrequent hazard events, such as a major earthquake that occurs on average once every 100 or 200 years or a tsunami that occurs only once every several hundred years, may pose very high risk for facilities at risk if the consequences are extreme. For example, consider the tsunami risk for a school where tsunamis are expected to occur once every 500 years which corresponds to about a ten percent chance of a tsunami over the next 50 years. The tsunami risk is extremely high if there is no natural high ground or other safe area that is reachable in the short time available (from the end of earthquake ground shaking that generates the tsunami and the arrival of the tsunami at the school) and the expected death toll is many hundreds of people. In this situation, tsunami mitigation is likely the highest priority mitigation measure for the district, despite the relatively low probability of occurrence, because of the high level of life safety risk. On the other hand some hazard events such as minor flooding or minor winter storms may occur many times per year with negligible or very minor consequences. In such cases, the level of risk from very frequent hazard events may be very low. A common mistake in hazard mitigation planning is to over-emphasize mitigation for hazard events that occur frequently but with only minor consequences and to under-emphasize mitigation for less frequent hazard events that have much larger, even catastrophic consequences. Further important technical details about the concepts involved in the quantitative evaluation of risks from natural hazards are provided in Chapter Six of this Washington State K–12 Facilities Hazard Mitigation Plan. “Mitigation” means actions taken to reduce the risk due to hazards. Mitigation actions reduce the potential for damages, losses, and casualties in future disaster events. Repair of buildings or infrastructure damaged in a disaster is not mitigation because repair simply restores a facility to its pre-disaster condition and does not reduce the potential for future damages, losses, or casualties. Hazard mitigation projects may be initiated proactively before a disaster or after a disaster has already occurred. In either case, the objectives of mitigation are always to reduce future damages, losses or casualties. Most mitigation projects are physical projects to reduce damages, economic losses and casualties. However, in some cases, the negative impacts of disasters can be reduced by enhancing emergency response and recovery operations. A few of the common types of mitigation projects are shown below in Table 1.1.
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Table 1.1 Common Mitigation Projects for K–12 Facilities
Hazard Example Mitigation Projects All Natural Replace buildings at high risk with new current code buildings Hazards Build new or replacement buildings outside of high hazard zones Construct vertical evacuation structures Tsunamis Enhance and practice evacuation procedures Structural retrofits for buildings Earthquakes Nonstructural retrofits for building elements and contents Elevate flood-prone buildings Construct flood walls or berms Floods Flood-proof existing buildings Improve storm water drainage systems, levees or channels Remodel buildings with fire-safe construction details Wildland/Urban Implement defensible space and fuel reduction measures Interface Fires Enhance and practice evacuation procedures Implement or improve lahar warning systems Volcanic Events Enhance and practice evacuation procedures Landslides Stabilize at risk slopes near buildings Public education programs to improve understanding of hazards Enhance emergency planning and recovery planning General Obtain flood or earthquake insurance
Install generators in schools designated as shelters The mitigation project list above is representative of common mitigation projects. It is not comprehensive since mitigation projects can encompass a broad range of other actions to reduce future damages, losses, and casualties. In evaluating possible mitigation projects for an at-risk campus or building, districts are encouraged to consider the following principles:
Avoid building schools in or near hazard zones such as tsunami inundation zones, flood zones, lahar zones and landslide zones; and replace existing buildings in such hazard zones with new buildings outside of these high-risk locations. Whenever possible, these are the most effective mitigation measures.
Replace buildings that are in poor overall condition, that may be functionally obsolete, and that have problems with electrical, mechanical, plumbing, HVAC systems, and energy efficiency with a new building. Retrofitting buildings with major seismic
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vulnerabilities is often expensive and generally does not provide the same level of seismic safety as a new current-code building.
Implement seismic and other hazard mitigation measures with other building upgrades (such as a new roof) which is often less expensive than doing them separately. Mitigation for seismic and other hazards should always be considered when buildings are undergoing remodel or modernization.
1.4 The Mitigation Process The key element for all hazard mitigation projects is that they reduce risk. The benefits of a mitigation project are the reduction in risk (i.e. avoided damages, losses, and casualties attributable to the mitigation project). In other words, benefits are simply the difference in expected damages, losses, and casualties before mitigation (as-is condition) and after mitigation. These important concepts are illustrated below in Figure 1.2.
Figure 1.2 Mitigation Projects Reduce Risk
RISK BEFORE MITIGATION BENEFITS OF MITIGATION
REDUCTION RISK IN RISK AFTER MITIGATION
Quantifying the benefits of a proposed mitigation project is an essential step in hazard mitigation planning and implementation. Only by quantifying benefits is it possible to compare the benefits and costs of mitigation to determine whether or not a particular project is worth doing (i.e. is economically feasible). Real world hazard mitigation planning almost always involves choosing between a range of possible alternatives that reduce risk, often with varying costs and varying effectiveness. Quantitative risk assessment is centrally important to hazard mitigation planning. When the level of risk is high, the expected levels of damages and losses are likely to be unacceptable and mitigation actions have a high priority. Simply stated, the greater the risk, the greater the urgency of undertaking mitigation. Conversely, when risk is moderate both the urgency and the benefits of undertaking mitigation are reduced. It is neither technologically possible nor economically feasible to eliminate risk
Page | 18 completely. When levels of risk are low and/or the cost of mitigation is high relative to the level of risk, the risk may be deemed acceptable (or at least tolerable). Furthermore, proposed mitigation projects that address low levels of risk, or where the cost of the mitigation project is large relative to the level of risk, are generally poor candidates for implementation.
Figure 1.3 Hazard Mitigation Planning Process Flowchart
Risk Assessment Quantify the Threat to the Built Environment
Is the Level of Risk Acceptable?
YES: Risk is Acceptable, NO: Risk is Not Acceptable -Mitigation Not Necessary -Mitigation Desired
-Identify Mitigation Alternatives -Find Solutions to Risk
-Prioritize Mitigation Alternatives -Use Benefit Cost Analysis and Related Tools
-Obtain Funding -Implement Mitigation Measures -Reduce Risk
Figure 1.3, above outlines the major steps in the OSPI hazard mitigation planning and implementation process applicable for K–12 facilities in Washington. The first step is quantitative evaluation (frequency and severity) of the hazards impacting school districts. The first step also includes evaluation of the inventory (people, buildings, infrastructure) exposed to these hazards. Together these hazard and exposure data determine the level of risk for specific locations, buildings or facilities. The next key step is to determine whether or not the level of risk posed by each of the hazards at a given location is acceptable or tolerable. If the level of risk is deemed acceptable or at least tolerable, then mitigation actions are not necessary or at least not a high priority. On the other hand, if the level of risk is deemed not acceptable or tolerable, then mitigation actions are desired. In this case, the hazard mitigation planning process progresses to a more detailed evaluation of specific mitigation alternatives, prioritization, funding and implementation
Page | 19 of mitigation measures. As with the determination of whether or not the level of risk posed by each hazard is acceptable or not, decisions about which mitigation projects to undertake can be made only by a school district and the residents within a school district.
1.5 The Role of Benefit-Cost Analysis in Hazard Mitigation Planning Benefit-cost analysis is powerful and can help communities provide solid, defensible answers to difficult socio-political-economic-engineering questions. Benefit-cost analysis is required for most FEMA-funded mitigation projects, under both pre-disaster and post-disaster mitigation programs. Thus, communities seeking FEMA funding must understand benefit-cost analysis. However, regardless of whether or not FEMA funding is involved, benefit-cost analysis provides a sound basis for evaluating and prioritizing possible mitigation projects for any natural hazard and may also be used to support local bond issues for mitigation projects. School districts considering whether or not to undertake mitigation projects must answer questions that don’t always have obvious answers, such as:
What is the nature of the hazard problem?
How frequent and severe are the hazard events?
Do we want to undertake mitigation measures?
What mitigation measures are feasible, appropriate, and affordable?
How do we prioritize between competing mitigation projects?
Are our mitigation projects likely to be eligible for FEMA funding? Detailed information about FEMA’s mitigation grant programs is available online. See http://www.fema.gov/grants. FEMA’s benefit-cost analysis software, detailed guidance on benefit-cost analysis, reference publications, and training courses are available online at https://www.fema.gov/benefit-cost- analysis.Technical assistance is also available at [email protected] or 1-855-540-6744. The following FEMA publications are recommended as general references for benefit-cost analysis: “What is a Benefit? Guidance for Benefit-Cost Analysis.” “BCA Reference Guide.” “Supplement to the Benefit-Cost Reference Guide.” These publications include guidance on categories of benefits for mitigation projects including various types of buildings, critical facilities, and infrastructure. The publications also provide simple, FEMA-standard methods to quantity the full range of benefits for most types of mitigation projects. The FEMA standard values in the BCA Reference Guide and the Supplement are the most current values in 2013 and should be used for benefit-cost analyses.
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1.6 Synopsis of Natural Hazards Affecting K–12 Facilities in Washington State Six natural hazards that pose the most risk to K–12 facilities in Washington State are considered in detail in this mitigation plan. They are: earthquakes, tsunamis, floods, wildland/urban interface fires, volcanic events, and landslides. There are also other natural hazards that pose less severe or more localized risk. They are considered in less detail and include avalanches, severe weather, and drought, etc. Disaster events for any of these natural hazards will result in damages and other economic losses and may also result in deaths and injuries. However, the hazards with the greatest potential to result in deaths and injuries are tsunamis, earthquakes, and volcanic lahars. Every K–12 facility in Washington State has a non-negligible level of earthquake hazard; although, the level of hazard varies markedly with location. Locations east of the Cascades have the lowest level of earthquake hazard, while locations on the Pacific Coast and the Puget Sound have the highest levels of earthquake hazard. Tsunamis, floods, lahars, and landslide hazards vary markedly with location and each of these hazards affects a relatively small fraction of the state, thus a relatively small fraction of K–12 facilities. However, for campuses at risk from these hazards, the level of risk may be high or very high. Most of Washington State is outside of fully urbanized areas, and thus many K–12 facilities are subject to wildland or wildland/urban interface fire hazards. The level of such fire hazards and risk varies markedly and depends on many factors including climate, topography, fuel loads, and the availability of fire suppression resources. The lesser natural hazards generally pose much less risk to K–12 facilities than the six major hazards discussed above. However, there may be a few locations with high risk from avalanches or other lesser hazards. Every K–12 facility in Washington is subject to severe weather including wind, snow, and ice storms. Wind, snow, and ice storms most commonly affect above ground utility lines with disruption of electric power but may also result in some damage to buildings especially from tree falls. For school districts, the primary impact of wind, snow, and ice storms are disruption of transportation and power outages which may result in school closures. Most storms do not result in severe damage to buildings, but severe storms may cause significant damage to some buildings. The remaining chapters of the Washington State K–12 Facilities Hazard Mitigation Plan include the following:
Chapter two provides a brief summary of OSPI and the K–12 districts and facilities.
Chapter three documents the planning process for the development of this hazard mitigation plan.
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Chapter four outlines OSPI’s hazard mitigation goals, objectives, and mitigation action items.
Chapter five documents OSPI’s process for implementing and periodically updating this hazard mitigation plan.
Chapter six summarizes the principles of risk assessments for natural hazards.
Chapters seven through twelve cover each of the major hazards addressed in this hazard mitigation plan, including: o Chapter Seven, Earthquakes. o Chapter Eight, Tsunamis. o Chapter Nine, Volcanic Hazards. o Chapter Ten, Floods. o Chapter Eleven, Wildland and Wildland/Urban Interface Fires. o Chapter Twelve, Landslides.
Chapter thirteen addresses other natural hazards which pose lesser risks to K–12 facilities or for which the risk is limited to only a few locations.
The Washington State K–12 Facilities Hazard Mitigation Plan does not address human-caused hazards such as hazardous materials incidents such as vehicle, rail, or aircraft accidents; terrorism or other deliberate malevolent acts. These hazards are simply outside the domain of natural hazard mitigation and are better addressed via emergency planning and emergency response agencies.
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Chapter Two: Community Profile
2.1 Overview The community affected by the Washington State K–12 Facilities Hazard Mitigation Plan is only, to a small extent, the Office of Superintendent of Public Instruction (OSPI). Rather, the community is predominantly the 295 K–12 school districts in Washington, including the students, teachers, other district staff, volunteers in schools, and the parents of students enrolled in schools. In a broader sense, the community is the entire state of Washington and all of the state’s residents because K–12 schools are largely funded by state and local taxes, and education is profoundly important and affects the well-being of everyone in Washington.
2.2 OSPI’s Mission and Responsibilities In collaboration with educators, students, families, local communities, business, labor and government partners, the Office of Superintendent of Public Instruction leads, supports, and oversees K–12 education, ensuring success of all learners. There are three major functions of OSPI which include: funding schools, collecting and managing school data, and assessing students. Within OSPI, School Facilities & Organization administers the K–12 Capital Budget and the School Construction Assistance Program (SCAP). This program assists local school districts with their school facilities and provides funding assistance for facility planning, new construction, and modernizations. OSPI has provided over $5.2 billion to school districts for school construction since 1986, equating to 79 million square feet of school space being newly built or modernized. The amount of funding school districts receive for construction varies depending on their wealth and ability to generate revenue. OSPI has developed processes to ensure that best practices and state requirements are met when K–12 facilities are being built using state funding. For the 2013–15 Biennium, OSPI oversees a $17 billion operating budget and $961 million capital budget. Most of the operating and capital budgets’ funds go to the school districts.
2.3 Washington State K–12 School Districts There are 295 K–12 school districts in Washington as shown in Figure 2.1 on the following page. The 295 districts have approximately 100,000 staff and have over 2,400 campuses with over 10,000 buildings. In addition to their educational functions, many schools have pre-school and after-school programs and many also serve as community centers, especially in smaller communities.
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Figure 2.1 Washington State School Districts
2.4 Washington State K–12 Students Washington State has a large and diverse body of K–12 students located throughout the state. The total student enrollment for the 2013 school year, including Pre-K, Full-K, Half-K and Grades 1–12 is 1,054,061, with approximately 80,000 students per grade in grades 1–12 and approximately 93,400 students in Pre-K and K. Enrollment by grade is shown in Table 2.1.
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Table 2.1 Washington State K–12 Student Headcount Enrollment 2013 School Year
Grade Enrollment
Pre K 12,478 Full K 39,879 Half K 41,044 1 80,632 2 78,995 3 78,805 4 78,333 5 77,419 6 79,034 7 79,452 8 79,359 9 83,086 10 80,813 11 78,581 12 85,151 Total 1,053,061 English proficiency affects several aspects of mitigation planning, including communications with students and parents, as well as evacuation planning. As shown below in Table 2.2, about 9.3 percent (98,420) of the students are less than fluent in English. Students whose English proficiency is below Level Four, about eight percent (86,358) of students, are identified as having limited English proficiency.
Table 2.2 English Proficiency
Number English Proficiency Level of Students Level 4 (Transitional) 12,062 Level 3 (Advanced English) 52,922 Level 2 (Intermediate English) 28,524 Level 1 (Beginning English) 3,532 No Score* 1,380 Total 98,420 The percentage of students from economically-disadvantaged homes is shown below in Table 2.3, based on the United States Department of Agriculture criteria for free or reduced cost school lunches. As shown, about 45 percent of students meet the requirements to receive free or reduced school lunches.
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Table 2.3 Students from Economically Disadvantaged Homes
Data Free Reduced Annual Income Limit for $29,055 $41,348 Households of 4 Persons Enrolled students in 402,039 74,255 Washington State Percent of Students 38.18% 7.05%
Table 2.4 Districts and Other K–12 Related Institutions by Student Enrollment
Student Number of Enrollment Districts <100 45 100 to 499 68 500 to 999 46 1,000-2,499 48 2,500-4,999 39 5,000-9,999 27 10,000 -49,999 30 >50,000 1
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Table 2.5 2013 School Year Student Headcount Enrollment by District
District Name P-12 Total K-12 Total District Name P-12 Total K-12 Total Aberdeen School District 3,281 3,224 Damman School District 45 45 Adna School District 593 591 Darrington School District 451 447 Almira School District 93 92 Davenport School District 554 551 Anacortes School District 2,750 2,717 Dayton School District 433 431 Arlington School District 5,497 5,449 Deer Park School District 2,515 2,494 Asotin-Anatone School District 616 610 Dieringer School District 1,528 1,512 Auburn School District 15,077 14,863 Dixie School District 27 27 Bainbridge Island School District 3,949 3,904 East Valley School District (Spokane) 4,544 4,479 Battle Ground School District 13,368 13,265 East Valley School District (Yakima) 3,053 3,026 Bellevue School District 18,951 18,896 Eastmont School District 5,719 5,653 Bellingham School District 11,164 11,095 Easton School District 103 103 Benge School District 12 12 Eatonville School District 1,814 1,799 Bethel School District 18,255 18,021 Edmonds School District 20,862 20,505 Bickleton School District 93 93 Ellensburg School District 3,125 3,079 Blaine School District 2,166 2,121 Elma School District 1,557 1,535 Boistfort School District 95 91 Endicott School District 97 96 Bremerton School District 5,056 4,901 Entiat School District 369 366 Brewster School District 947 922 Enumclaw School District 4,437 4,407 Bridgeport School District 827 816 Ephrata School District 2,357 2,332 Brinnon School District 29 29 Evaline School District 51 51 Burlington-Edison School District 3,838 3,799 Everett School District 19,197 18,921 Camas School District 6,418 6,375 Evergreen School District (Clark) 26,445 26,295 Cape Flattery School District 450 446 Evergreen School District (Stevens) 27 27 Carbonado School District 182 182 Federal Way School District 22,500 22,193 Cascade School District 1,293 1,280 Ferndale School District 5,179 5,102 Cashmere School District 1,517 1,496 Fife School District 3,587 3,548 Castle Rock School District 1,299 1,286 Finley School District 927 919 Centerville School District 76 76 Franklin Pierce School District 7,557 7,474 Central Kitsap School District 11,082 10,988 Freeman School District 901 895 Central Valley School District 13,066 12,965 Garfield School District 97 97 Centralia School District 3,595 3,520 Glenwood School District 71 69 Chehalis School District 2,964 2,942 Goldendale School District 972 963 Cheney School District 4,283 4,206 Grand Coulee Dam School District 705 700 Chewelah School District 843 833 Grandview School District 3,627 3,594 Chimacum School District 1,099 1,085 Granger School District 1,535 1,509 Clarkston School District 2,710 2,669 Granite Falls School District 2,089 2,070 Cle Elum-Roslyn School District 890 883 Grapeview School District 204 203 Clover Park School District 12,765 12,427 Great Northern School District 48 47 Colfax School District 644 640 Green Mountain School District 147 147 College Place School District 847 833 Griffin School District 651 646 Colton School District 171 169 Harrington School District 100 100 Columbia (Stevens) School District 154 154 Highland School District 1,214 1,198 Columbia (Walla Walla) School District 859 847 Highline School District 19,274 19,017 Colville School District 1,863 1,828 Hockinson School District 1,914 1,902 Concrete School District 548 543 Hood Canal School District 291 276 Conway School District 404 397 Hoquiam School District 1,662 1,642 Cosmopolis School District 142 137 Inchelium School District 217 211 Coulee-Hartline School District 188 184 Index School District 32 31 Coupeville School District 945 927 Issaquah School District 18,832 18,615 Crescent School District 295 294 Kahlotus School District 53 52 Creston School District 106 106 Kalama School District 940 932 Curlew School District 205 203 Keller School District 19 19 Cusick School District 273 273 Kelso School District 4,859 4,818
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Table 2.5–Continued 2013 School Year Student Headcount Enrollment by District
District Name P-12 Total K-12 Total District Name P-12 Total K-12 Total Kennewick School District 16,987 16,798 North Franklin School District 2113 2078 Kent School District 27725 27445 North Kitsap School District 6303 6187 Kettle Falls School District 887 878 North Mason School District 2153 2106 Kiona-Benton City School District 1,477 1,457 North River School District 51 51 Kittitas School District 662 656 North Thurston Public Schools 14,804 14,584 Klickitat School District 96 96 Northport School District 238 236 La Center School District 1,621 1,610 Northshore School District 20652 20403 La Conner School District 630 625 Oak Harbor School District 5,635 5,512 LaCrosse School District 71 71 Oakesdale School District 105 104 Lake Chelan School District 1,416 1,401 Oakville School District 260 252 Lake Quinault School District 165 165 Ocean Beach School District 963 947 Lake Stevens School District 8345 8262 Ocosta School District 661 653 Lake Washington School District 26,361 26,154 Odessa School District 216 213 Lakewood School District 2387 2369 Okanogan School District 1,119 1,103 Lamont School District 32 32 Olympia School District 9,529 9,373 Liberty School District 418 413 Omak School District 5273 5231 Lind School District 183 179 Onalaska School District 750 743 Longview School District 6821 6693 Onion Creek School District 35 35 Loon Lake School District 237 235 Orcas Island School District 867 858 Lopez School District 227 224 Orchard Prairie School District 61 61 Lyle School District 225 223 Orient School District 115 114 Lynden School District 2,902 2,853 Orondo School District 161 157 Mabton School District 915 911 Oroville School District 597 584 Mansfield School District 77 77 Orting School District 2,375 2,350 Manson School District 672 663 Othello School District 4,018 3,967 Mary M Knight School District 199 198 Palisades School District 23 23 Mary Walker School District 510 504 Palouse School District 197 192 Marysville School District 11563 11375 Pasco School District 16,722 16,607 McCleary School District 289 287 Pateros School District 302 302 Mead School District 9,619 9,562 Paterson School District 111 108 Medical Lake School District 1,902 1,863 Pe Ell School District 285 283 Mercer Island School District 4,345 4,318 Peninsula School District 9049 8953 Meridian School District 1,802 1,768 Pioneer School District 696 661 Methow Valley School District 609 604 Pomeroy School District 325 323 Mill A School District 23 23 Port Angeles School District 3,791 3,752 Monroe School District 6,844 6,769 Port Townsend School District 1,268 1,250 Montesano School District 1312 1285 Prescott School District 357 352 Morton School District 310 306 Prosser School District 2854 2821 Moses Lake School District 8159 8039 Pullman School District 2604 2542 Mossyrock School District 534 530 Puyallup School District 21207 20982 Mount Adams School District 1002 996 Queets-Clearwater School District 24 22 Mount Baker School District 1883 1846 Quilcene School District 542 542 Mount Pleasant School District 66 66 Quillayute Valley School District 3,113 3,099 Mount Vernon School District 6,480 6,396 Quincy School District 2,787 2,745 Mukilteo School District 15127 15009 Rainier School District 821 816 Naches Valley School District 1354 1351 Raymond School District 671 661 Napavine School District 784 778 Reardan-Edwall School District 603 598 Naselle-Grays River Valley School District 636 636 Renton School District 15237 14990 Nespelem School District 133 127 Republic School District 349 346 Newport School District 1044 1031 Richland School District 12102 11953 Nine Mile Falls School District 1538 1516 Ridgefield School District 2195 2181 Nooksack Valley School District 1582 1553 Ritzville School District 330 325 North Beach School District 640 632 Riverside School District 1,450 1,437
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Table 2.5–Continued 2013 School Year Student Headcount Enrollment by District
District Name P-12 Total K-12 Total District Name P-12 Total K-12 Total Riverview School District 3,326 3,295 University Place School District 5655 5590 Rochester School District 2226 2196 Valley School District 965 958 Roosevelt School District 24 24 Vancouver School District 23084 22885 Rosalia School District 195 194 Vashon Island School District 1562 1549 Royal School District 1,625 1,605 Wahkiakum School District 413 408 San Juan Island School District 838 831 Wahluke School District 2,293 2,270 Satsop School District 56 56 Waitsburg School District 291 288 Seattle Public Schools 49,572 48,978 Walla Walla Public Schools 6,320 6,249 Sedro-Woolley School District 4,323 4,268 Wapato School District 3,449 3,412 Selah School District 3,484 3,446 Warden School District 975 959 Selkirk School District 243 243 Washougal School District 3161 3136 Sequim School District 2870 2830 Washtucna School District 61 60 Shaw Island School District 14 14 Waterville School District 280 278 Shelton School District 4225 4112 Wellpinit School District 511 507 Shoreline School District 9,023 8,933 Wenatchee School District 7,883 7,782 Skamania School District 77 77 West Valley School District (Spokane) 3822 3771 Skykomish School District 42 42 West Valley School District (Yakima) 4946 4889 Snohomish School District 10172 10084 White Pass School District 424 421 Snoqualmie Valley School District 6465 6356 White River School District 3,630 3,595 Soap Lake School District 472 468 White Salmon Valley School District 1320 1299 South Bend School District 542 534 Wilbur School District 271 270 South Kitsap School District 9,472 9,370 Willapa Valley School District 321 321 South Whidbey School District 1503 1489 Wilson Creek School District 146 146 Southside School District 204 204 Winlock School District 680 677 Spokane School District 29,457 29,026 Wishkah Valley School District 148 148 Sprague School District 72 69 Wishram School District 84 82 St. John School District 158 156 Woodland School District 2251 2240 Stanwood-Camano School District 4557 4501 Yakima School District 15,708 15,424 Star School District 5 5 Yelm School District 5676 5619 Starbuck School District 28 28 Zillah School District 1312 1300 Stehekin School District 8 8 Steilacoom Hist. School District 3,114 3,061 Steptoe School District 29 29 Stevenson-Carson School District 966 946 Sultan School District 1,946 1,927 Summit Valley School District 83 83 Sumner School District 8765 8676 Sunnyside School District 6,496 6,433 Tacoma School District 29156 28978 Taholah School District 191 185 Tahoma School District 7864 7785 Tekoa School District 175 173 Tenino School District 1226 1204 Thorp School District 121 119 Toledo School District 759 754 Tonasket School District 1099 1079 Toppenish School District 4012 3945 Touchet School District 238 235 Toutle Lake School District 606 600 Trout Lake School District 198 197 Tukwila School District 2959 2937 Tumwater School District 6414 6323 Union Gap School District 622 616
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Chapter Three: Mitigation Planning Process
3.1 Washington State K–12 Facilities Hazard Mitigation Plan: Overview The Washington State K–12 Facilities Hazard Mitigation Plan is the first mitigation planning effort in the nation to specifically address the risks from natural hazards to K–12 school facilities on a statewide basis. The mitigation plan focuses on six natural hazards that pose the greatest threats to K–12 facilities in Washington They are earthquakes, tsunamis, floods, wildland/urban interface fires, volcanic events and landslides. The mission statement for the Washington State K–12 Facilities Hazard Mitigation Plan is: Proactively facilitate and support statewide resources and programs that assist school districts in making K–12 schools in Washington State more disaster resistant and disaster resilient. This mitigation plan improves the understanding of risks to K–12 facilities from natural hazards and identifies which campuses are subject to significant risk from one or more natural hazards. The plan facilitates the development of hazard mitigation plans by individual school districts and provides a basis for prioritizing mitigation measures to reduce risks for campuses at high risk. Main steps in the mitigation planning and implementation process are shown below.
Figure 3.1 Main Steps in the Mitigation Planning and Implementation Process Implementation of Mitigation Measures School District Hazard Mitigation Plans
OSPI K–12 Facilities Hazard Mitigation Plan
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Further details of main steps in mitigation planning and implementation process are shown below.
Table 3.1 Main Steps in Mitigation Planning and Implementation Process
Implement Mitigation Measures to Improve Life Safety and Reduce Damages for K–12 Facilities
The OSPI mitigation planning effort includes detailed analysis of at least ten specific mitigation projects. This addresses high risk facilities including completion of benefit-cost analyses that are necessary for FEMA mitigation grant funding eligibility.
The risks to K-12 facilities in Washington from natural hazards will be reduced as mitigation projects to provide life safety and reduce damages are implemented as funding becomes available.
Hazard Mitigation Plans for Schools Districts
The OSPI mitigation planning effort includes workshops, toolkits and templates to facilitate development of mitigation plans for individual school districts.
School district mitigation plans include more detailed risk assessments for campuses and buildings to develop priorities for mitigation measures that reduce risk and are feasible and cost-effective.
The OSPI mitigation planning effort includes support for development of district-specific mitigation plans for districts that are planning partners for the OSPI planning effort. The tools developed by OSPI will be available on an ongoing basis to support future development of additional district- specific mitigation plans.
Washington State K–12 Facilities Hazard Mitigation Plan
Statewide assessment of natural hazards that pose risks to K–12 facilities.
Identification of campuses that have significant risks from one or more natural hazards.
Provides the foundation of knowledge to deal with natural hazards that pose significant risk to school facilities pragmatically and cost-effectively by focusing attention on campuses with higher risks.
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3.2 Mitigation Planning Process Documentation Participants in the Planning Process The Washington State K–12 Facilities Hazard Mitigation plan was developed by OSPI staff with technical support by a consulting team led by Kenneth A. Goettel of Goettel & Associates Inc. and Sandra Davis of ECO Resource Group. The 2013 Washington K–12 Facilities Mitigation Planning Process began in June 2012 with a kick-off meeting between the consulting team and OSPI. Stakeholder involvement has been an important part of creating the Washington State K–12 Facilities Hazard Mitigation Plan. The plan was developed in close coordination with a planning team that provided perspective, guidance and review of draft materials throughout the mitigation planning process. The members of the planning team are key stakeholders that possess knowledge and understanding of K–12 facilities in the state of Washington. The planning team included representatives from school districts, educational associations, Educational Service Districts, and facility experts with experience working with school districts throughout the state. The members of the planning team are shown in Table 3.2 below.
Table 3.2 Planning Team Members
Organization Participant Washington State School Directors' Chuck Namit (North Thurston School District) and John Association (WSSDA) Mortenson (Rochester School District)
Washington Association of School Administrators (WASA) Rob Van Slyke (Bethel School District)
Washington State Risk Management Pool (WSRMP) Mary Sue Linville and Sara Hoover
Washington Association of School Business Officials (WASBO) Marina Tanay
BLRB Arch., OSPI Citizens Advisory Panel member (CAP) Tom Bates
Ocosta School District and planning partner Paula Akerlund (Superintendent)
Washington Association of Sheriffs and Police Chiefs (WASPC) Bruce Kuennen
Meng Analysis Eric Meng
ESD 101 Eric Dickson
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The major roles and responsibilities of the planning team, with technical support from the consultants and oversight from OSPI, included:
Preparing for, attending, and actively participating in planning team meetings throughout the course of the Washington State K–12 Facilities Hazard Mitigation Planning Project.
Reviewing materials provided by OSPI and the consultants in a timely manner and providing thoughtful and constructive comments.
Participating in public meetings or technical assistance workshops.
Focusing on the overall good of Washington State’s schools and the needs of their multiple stakeholders (e.g. teachers, students, parents, etc.). Other planning participants included subject matter experts from other agencies, including Washington Emergency Management, Washington Department of Natural Resources, Washington Department of Ecology, the United States Geological Survey, and others who provide technical expertise about natural hazards and reviews of draft materials. The planning process also included outreach to stakeholders for feedback on the mitigation plan through a broadly distributed electronic survey posted on OSPI’s website. This survey gave teachers, educational staff, parents, and other interested parties the opportunity to provide feedback and suggestions. The results of this survey are summarized in Section 3.3. A draft of the Washington State K–12 Facilities Hazard Mitigation Plan was posted on OSPI’s website for review and comment by the public before it was finalized. Outreach and engagement of stakeholders will also be an essential part of the planning process for school districts developing their own hazard mitigation plan.
Washington State K–12 Facilities Hazard Mitigation Plan Planning Team Meetings The convening of a planning team began in the fall of 2012 and was coordinated by the lead consultants and OSPI. Members of the planning team, along with OSPI staff and consulting staff, met on the following dates:
November 28, 2012.
February 28, 2013.
May 30, 2013.
November 5, 2013.
September 30, 2014. Future meetings will be determined as necessary to assist Planning Partners School Districts
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Survey Questionnaire The OSPI Survey Regarding Increasing Life Safety Before Disaster Strikes was provided statewide to school districts, educators, parents, students and the public from December 17, 2012 until July 17, 2013. During this period, 242 people responded to the survey of which 83 percent were school district personnel, nine percent parents, five percent interested citizens, and three percent other agency (not school district) personnel. The majority of respondents (70 percent) reside in five counties (Mason, Thurston, Cowlitz, Clark and Island) (Table 3.3 and Figure 3.2).
Table 3.3 Survey Responses by County
Grays Benton 1 Harbor 1 Mason 82 Spokane 8
Chelan 3 Island 10 Okanogan 7 Stevens 4
Clallam 1 King 3 Pend Oreille 1 Thurston 38
United Clark 11 Kitsap 2 Pierce 7 States 2
Walla Cowlitz 26 Kittitas 4 Skagit 1 Walla 1
Douglas 4 Klickitat 3 Skamania 1 Whatcom 2
Ferry 3 Lewis 2 Snohomish 3 Whitman 1
Grant 3 Lincoln 1 Kitsap 1 Yakima 5
242 Respondents, 31 Counties (out of 39)
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Figure 3.2 Survey Responses by County
Counties in gray had no respondents
Concerns about Consequences of Natural Hazard Events The survey results show that if natural disasters were to occur in the respondents’ communities, most (78 percent) were concerned about deaths and injuries in schools, with less concern (15 percent) where school operations were simply disrupted (closures or relocation), or (8 percent) where there were economic losses or loss of school days.
Figure 3.3 Concerns about Natural Hazard Events
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Goals for Addressing Risks for Schools Continuing a pattern of higher concern for events that would cause deaths or injuries, respondents rated the goal of reducing death or injury higher than other goals, including reducing disruption of classes, disruption of pre- or after-school programs, or property damage (60 percent rated the goal as Very Important).
Figure 3.4 Risk Reduction Goals
Level of Threat from Different Hazards Respondents were asked to rate the threats of various hazards that might occur and affect schools. There are some differences between counties and regional differences between the east and west sides of Washington, as expected, because of the geographic variability in the historical occurrence of disaster events. However, earthquakes, floods, severe weather and wildland/urban interface fires were ranked the highest threats and had the greatest number of “Very High” and “High” responses for the rankings.
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Figure 3.5 Perceived Threat by Hazard Type
What do you believe is the level of threat to K-12 schools, facilities and people in Washington State from the following hazards?
300 250 Very Low 200 Low 150 Moderate 100 High Very High 50
0
Fires
Floods
Severe
Drought
Events
Weather
Volcanic
Tsunamis
Landslides
Avalanches Earthquakes
Concerns about Hazards of Differing Frequency and Severity In a similar pattern, more respondents had Very High concern about natural hazard events that would be less frequent but of greater magnitude, where loss of life was a greater issue. There is a clear distinction in numbers between Low and High Concern for frequent events, and a general trend toward More Concern about less frequent events up to the 100 year cycle. There is an almost even spread of concern about the very infrequent event (1,000 year return period – 0.1 percent chance very year), showing a large diversity of perspectives even though there are more Very High concerns.
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Figure 3.6 Concerns about Hazard Frequency and Damage
What level of concern do you have regarding the following types of natural hazard disaster situations that could affect schools, facilities and people?
300
250 Very Low 200 Low 150 Moderate
100 High Very High 50
0
death.
deaths.
or injuries. or
$5,000,000
200 deaths. 200
Very infrequent Very
minor damage. minor
school closures, school
events, 10 years , years 10 events,
events, few years, few events,
Relatively frequent Relatively
$500,000 damages, $500,000
Relatively infrequent Relatively
no deaths or injuries. or deaths no
Relatively infrequent Relatively
damages, no deaths no damages,
Relatively infrequent Relatively
events , 1,000 years, 1,000 , events
events, 50 years, one years, 50 events,
Very frequent events, frequent Very disrupt transportation, disrupt events , 100 years, 10 years, 100 , events Strategies for Addressing Risks for Schools Respondents also provided input on risk reduction strategies. More people strongly agree that the best strategy is to avoid building new schools in areas that are at high risk from natural hazards. In addition, most respondents agree that more resources should be available to school districts to implement risk reduction measures, and the state should be more proactive in helping to identify schools that are at high risk.
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Figure 3.7 Risk Reduction Strategies
Please tell us about your level of support regarding the following strategies related to reducing risks to schools from natural disasters:
300 250 200 150 100 Not Sure 50 Disagree Strongly 0 Disagree More resources should Washington State should New schools should not Neutral be available to help be more proactive in be built in areas that are Agree school districts helping districts identify at high risk from natural Agree Strongly implement risk reduction schools that are at high hazards. measures for schools risk from natural that are at high risk from hazards. natural hazards.
Other Risk Reduction Strategies Respondents suggested a number of other strategies to reduce risk from natural disasters related to communications including evacuation routes, funding, hazard identification, building safety, planning, practice drills and training. In addition to commenting on natural disasters, some respondents suggested risk reduction strategies for human-caused disasters in schools.
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Chapter Four: Mission Statement Goals, Objectives, and Action Items
4.1 Overview The overarching purpose of the Washington State K–12 Facilities Hazard Mitigation Plan is to reduce the impact of future natural disasters on schools in Washington State. That is, to make K– 12 schools more disaster resistant and disaster resilient by reducing their vulnerability to disasters and by enhancing the capability of school districts to respond effectively to, and recover quickly from, future natural disaster events. The Washington State K–12 Facilities Hazard Mitigation Plan provides the foundation for mitigation plans for individual school districts Individual mitigation plans address natural hazards posing risk to district facilities in more detail than is possible in the statewide plan. Completely eliminating risk to K–12 schools in Washington State from future natural disasters is neither technologically possible nor economically feasible. However, substantially reducing negative impacts of future disasters on schools is achievable with adoption of pragmatic hazard mitigation plans and with ongoing implementation of risk reduction strategies and action items. School Districts that consider risk reduction strategies and action items, when implementing OSPI’s existing programs, will help facilitate districts moving schools toward a safer and more disaster resistant future in a cost-effective manner. This Washington State K–12 Facilities Hazard Mitigation Plan provides the framework and guidance for both short and long-term proactive steps that can be taken to:
Protect life safety.
Reduce property damage.
Minimize economic losses and disruption.
Shorten the recovery period from future disasters. The school districts’ hazard mitigation plans will meet FEMA’s (Federal Emergency Management Agency) mitigation planning requirements so that participating school districts will be eligible to apply for pre- and post-disaster mitigation grant funding from FEMA. The K–12 Facilities Hazard Mitigation Plan provides a four-step framework to focus attention and action on effective mitigation strategies to reduce risks from natural hazards to schools in Washington State. That framework is 1) Mission Statement, 2) Goals, 3) Objectives and 4) Action Items.
Mission Statement. The Mission Statement states the purpose and defines the primary function of the Washington State K–12 Facilities Hazard Mitigation Plan. The Mission Statement is an action-oriented summary that answers the question “Why develop a hazard mitigation plan?”
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Goals. Goals identify priorities and specify how OSPI intends to work toward reducing the risks from natural and human-caused hazards. The Goals represent the guiding principles toward which mitigation efforts are directed. Goals provide focus for the more specific issues, recommendations and actions addressed in Objectives and Action Items.
Objectives. Each Goal has Objectives which specify the directions, methods, processes, or steps necessary to accomplish the plan’s Goals. Objectives then lead directly to specific Action Items.
Action Items. Action items are specific well-defined strategies, activities or projects that work to reduce risk. That is, the Action Items represent the implemental steps necessary to achieve the Mission Statement, Goals and Objectives.
4.2 Mission Statement The Mission of the Washington State K–12 Facilities Hazard Mitigation Plan is: Proactively facilitate and support statewide resources and programs that assist school districts in making K–12 schools in Washington State more disaster resistant and disaster resilient. The Washington State K–12 Facilities Hazard Mitigation Plan documents OSPI’s commitment to promote sound public policies designed to help minimize the negative impacts of future natural disaster events on K–12 schools in Washington State. This is accomplished through mitigation actions at the state level and by encouraging and facilitating mitigation planning efforts in school districts throughout the state.
4.3 Mitigation Plan Goals and Objectives Mitigation plan Goals and Objectives guide the direction of future policies and activities aimed at reducing risk and preventing loss from disaster events. The Goals and Objectives listed here serve as guideposts and checklists as OSPI and the school districts begin the ongoing, long-term process of implementing mitigation Action Items to reduce the risks to K–12 school facilities from natural disasters. Washington State K–12 Facilities Hazard Mitigation Plan’s Goals and Objectives are based broadly on, and consistent with, the goals established by the Washington State Enhanced Hazard Mitigation Plan. However, the specific priorities, emphasis and language in this mitigation plan are OSPI’s. These goals were developed with extensive input and priority setting by the planning team, other stakeholders, and school districts.
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Goal One: Protect Life Safety Objectives:
Enhance life safety by supporting school districts’ efforts to improve existing schools, and build new schools that minimize the potential for deaths and injuries from future disaster events.
Enhance life safety by improving public awareness of earthquakes, tsunamis, volcanic events and other natural hazards that pose a substantial life safety risk to students and staff in Washington State schools.
Goal Two: Protect K–12 School Facilities Objectives:
Identify school facilities that are at high risk from one or more natural hazards.
Assist school districts in conducting risk assessments for school facilities that are at high risk to determine cost effective mitigation actions and eliminate or minimize risk.
Assist school districts in implementing mitigation measures for school facilities that have been evaluated and found to have an unacceptable level of risk.
Provide school districts information to help ensure that new school facilities are adequately designed and properly located to minimize life safety risk and damages in future natural disaster events.
Goal Three: Enhance Emergency Planning, Disaster Response and Post-Disaster Recovery Objectives:
Encourage and facilitate development of effective emergency evacuation plans for school districts that have facilities at risk from natural disasters that may result in deaths or injuries unless effective evacuation is planned. This includes schools located in tsunami inundation zones and schools at risk from volcanic lahars, wildland fires and floods.
Provide tools and guidance that enhance emergency planning to facilitate effective response and recovery from future natural disaster events.
Increase collaboration and coordination between OSPI, school districts, local governments, utilities, businesses and citizens to prepare for and recover from future natural disaster events.
Develop and implement education and outreach efforts to increase awareness of natural hazards throughout the school community including districts, teachers, parents and students.
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Goal Four: Encourage and Facilitate Development of Hazard Mitigation Plans for School Districts Objectives:
Encourage school districts to develop hazard mitigation plans, with district-specific mitigation Goals, Objectives, and Action Items. These hazard mitigation plans will have more detailed risk assessments than possible with the Washington State K–12 Facilities Hazard Mitigation Plan.
Provide guidance, risk assessment data and templates, and a mitigation planning toolkit to facilitate development of robust mitigation plans by school districts, while minimizing the effort necessary to do so.
Provide information on resources, tools, partnership opportunities and funding resources to assist school districts to implement mitigation activities.
4.4 Mitigation Planning and Implementation Priorities Nearly all school facilities are necessary and important for providing educational services. Nevertheless, for mitigation planning, school buildings are often given a higher priority than administrative or support buildings. Because life safety is generally the paramount concern for schools, high occupancy buildings are often given a higher priority than low occupancy buildings. Schools that are designated as emergency shelters are often identified as critical facilities in local hazard mitigation plans. Therefore, if the risk assessment identifies substantial vulnerabilities and high risk to one or more natural hazards, critical facilities are given a higher priority for risk assessments and implementing mitigation measures. Mitigation Goals, Objectives and Action Items may vary significantly from district to district depending on each district’s exposure to natural hazards, district-specific conditions, facilities, and district-specific priorities.
4.5 Washington State K–12 Facilities Hazard Mitigation Plan Action Items The Mission Statement, Goals and Objectives for the Washington State K–12 Facilities Hazard Mitigation Plan (as outlined above) are achieved via implementation of specific mitigation Action Items. Action Items may include refinement of policies, data collection to better characterize hazards or risk, education, outreach or partnership-building activities, as well as specific engineering or construction measures to reduce risk from one or more hazards to specific buildings, facilities, or infrastructure within K–12 facilities in Washington State. Action Items identified and prioritized during the development of the Washington State K–12 Facilities Hazard Mitigation Plan are summarized in the table on the following page.
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Table 4.1 Multi-Hazard Mitigation Action Items
Plan Goals Addressed
Coordinating Hazard Action Item Timeline Organizations
Protect Protect
Enhance Enhance Enhance
Facilities Planning Planning
Education Mitigation
Life Life Safety
Emergency Emergency
Awareness and Awareness Multi-Hazard Mitigation Action Items
Long-Term Encourage, facilitate and support districts' efforts in OSPI Ongoing X X X X X #1 developing mitigation plans. Encourage, facilitate and support districts' efforts to develop Long-Term evacuation plans for natural hazards events such as OSPI Ongoing X X X #2 tsunamis and lahars that pose acute life safety risk. Encourage, facilitate and support districts' efforts in Long-Term conducting risk assessments and in implementing mitigation OSPI Ongoing X X X X X #3 measures for facilities that are determined to have unacceptable levels of risk from natural hazards. Encourage, facilitate and support district's efforts to ensure Long-Term that new facilities are adequately designed and well-sited to OSPI Ongoing X X X X #4 minimize risk from natural hazards. Long-Term Maintain, update and enhance facility data and natural OSPI Ongoing X X X X X #5 hazards data in the ICOS database. Long-Term Develop and distribute educational materials regarding OSPI Ongoing X X X X X #6 natural hazards, vulnerability and risk for K-12 facilities. Alert districts when a declared disaster covers their district Long-Term and encourage, facilitate and support districts' efforts to OSPI Ongoing X X X #7 obtain grant funds that may be available for post-disaster repairs and/or mitigation projects. Long-Term Encourage, facilitate and support districts' efforts to maintain OSPI Ongoing X X X X X #8 and update their mitigation plans. Encourage, facilitate and support districts to seek funds to Long-Term implement mitigation projects through grants and other OSPI Ongoing X X #9 programs.
Long-Term Ensure that OSPI-occupied facilities have an adequate level of OSPI Ongoing X X X X #10 seismic performance
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Chapter Five: Mitigation Plan Implementation and Updating
5.1 Overview For the Washington State K–12 Facilities Hazard Mitigation Plan to be effective, it has to be implemented gradually over time as resources become available and continually evaluated and periodically updated. OSPI does not have direct responsibility for its own facilities (which are managed and maintained by the Washington Department of Enterprise Services) nor school facilities (which are managed and maintained by individual school districts. Rather, OSPI’s role is primarily encouraging and helping to facilitate implementation of mitigation projects by school districts. OSPI’s role in implementing and updating the mitigation plan has two main elements:
Continue to support and facilitate implementation of mitigation measures through maintenance and enhancement of the ICOS Pre-Disaster Mitigation Database and through providing guidance and technical assistance to school districts.
Periodic evaluation and update of the mitigation programs for K–12 facilities in Washington. This effort will include compiling and updating the ICOS Pre-Disaster Mitigation Database with the latest facility and hazard information. This also includes identifying elements that are working effectively and those that may not be, with revisions and improvements in mitigation goals, objectives, and action items, as necessary.
5.2 Coordinating Body OSPI will have an Internal Implementation Team which will consist of staff from the School Facilities and Organization Section (SF&O), School Safety Center, and other OSPI sections as are deemed necessary. The internal implementation team will meet on a periodic basis, as is needed to ensure successful implementation of the mitigation planning effort by OSPI and participating school districts.
5.3 Implementation and Integration into Ongoing Programs, Policies and Practices The Washington State K–12 Facilities Hazard Mitigation Plan is an educational and guidance document, not a regulatory document. Thus implementation of the objectives, goals and action items can be accomplished most effectively by fully integrating the mitigation plan and other materials developed during the planning process guidance into existing OSPI programs, policies and practices. OSPI will work with school districts that are participating in various school facility grant funding programs administered by OSPI, to promote hazard mitigation planning efforts by the school districts. Any action by a school district to undertake hazard mitigation planning will be
Page | 45 voluntary. The role of OSPI is to provide technical assistance and guidance. This includes, but is not limited to, the following activities and programs:
Site Planning. OSPI SF&O will inform school districts that are in the processing of siting a new school facility to use the PDM tools in the ICOS Pre-Disaster Mitigation Database to determine whether a potential site is at high risk from one or more natural hazards. OSPI SF&O will provide technical support to assist school districts to access and use the ICOS Pre- Disaster Mitigation Database.
Study and Survey. OSPI SF&O will promote school districts undertaking Study and Survey efforts to gather facility level information regarding exposure to natural hazards, in order to better understand the risk to natural hazards that their districts face. Additional funding in a study and survey grant will be provided for school districts to collect facility information related to natural hazards. School districts that volunteer to collect additional facility information related to natural hazards will be encouraged to use the mitigation planning toolkit in the ICOS Pre-Disaster Mitigation Database to develop a mitigation plan. OSPI SF&O will provide technical support to assist school districts to access and use the ICOS Pre-Disaster Mitigation Database, including the mitigation planning toolkit.
School Construction Assistance Program. School districts seeking state-assistance funding for a modernization project through OSPI SF&O must incorporate all Washington State building codes (building, fire, plumbing, mechanical, etc.) current at the time of permit review, including seismic retrofits. Modernization projects that do not meet current seismic code requirements and have overall building condition issues are given priority for funding consistent with WAC 392.343.515.
School Mapping. OSPI SF&O will promote school districts, who are currently undertaking school mapping, to consider developing evacuation routes for any applicable natural hazards (e.g. tsunami, volcanic lahars, earthquake etc.) based on the analysis in the ICOS Pre- Disaster Mitigation Database.
5.4 Periodic Evaluation and Updating OSPI developed a process for regularly reviewing and updating the Hazard Mitigation Plan and related program activities. The Internal Implementation Team will review the plan at least annually, as well as after significant disaster events affecting school facilities in Washington State. The Internal Implementation Team will be responsible for tracking progress of the mitigation actions in the Plan. These reviews will provide opportunities to incorporate new information into the Plan and the ICOS Pre-Disaster Mitigation Database systems as well as remove outdated items and information. This will also be the time to recognize success of both OSPI and the districts in implementation of the action items.
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One important task will be to document mitigation projects completed by districts. OSPI will maintain a record of completed projects as examples to encourage other districts to implement similar projects. The Internal Implementation Team will assess whether and to what extent:
The plans goals, objectives and action items still address current and future expected conditions?
The mitigation action items accurately reflect OSPI’s mission and mitigation priorities?
The technical hazard, vulnerability and risk data has been updated or changed?
Current resources are adequate for implementing OSPI’s Hazard Mitigation Plan? If not, are there other resources that may be available?
There are any problems or impediments to implementation? If so, what are the solutions?
Other agencies, partners, and the public participated as anticipated? If not, what measures can be taken to facilitate participation?
There have been changes in federal and/or state laws pertaining to hazard mitigation in Washington State?
The FEMA requirements for the maintenance and updating of district hazard mitigation plans changed?
What can OSPI and districts learn from declared federal and/or state hazard events in that have significantly affect school facilities in Washington?
Previously implemented mitigation measures performed well in recent hazard events?
More counties have begun coordinating with school districts to develop mitigation plans? If so, are the OSPI planning tools being used to assist that planning effort? Another important task will be the periodic updating of the information in the ICOS Pre-Disaster Mitigation Database. This will include:
Updating hazard data in ICOS as new data becomes available from the United States Geological Survey, FEMA, Washington Department of Natural Resources, and other agencies.
Reviewing and updating the facility inventory data in the mitigation plan as new campuses and buildings are built and as districts continue to input campus-level and building-level data into ICOS.
Compiling and analyzing the latest hazard and facility information to provide a better understanding of the overall risk to school facilities from natural hazards across the state.
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Chapter Six: Natural Hazards Risk
6.1 Overview The essence of mitigation planning for natural hazards is to:
Identify facilities that have an unacceptably high level of risk from one or more natural hazards.
Evaluate ways to mitigate (reduce) the impacts of future disasters on these facilities. Implement mitigation measures to eliminate or reduce the risk. Risk from natural hazards means the chance of death, injury, damage or economic loss. Risk is best expressed quantitatively by estimates of the likely extent of damage and economic losses and the numbers of deaths and injuries in future disaster events that may affect a given K–12 facility. Evaluation of natural hazards and estimates of risk have considerable uncertainties: it is not possible to predict where or when a given natural hazard event will occur or exactly how severe the damages, losses, or casualties may be for an affected facility. For any given natural hazard event, the damages, losses, and casualties may be higher or lower than pre-event estimates. Mitigation planning can provide meaningful estimates of the probabilities of future disaster events affecting a given K–12 facility and can identify which hazards pose the greatest threats to each K–12 facility. Mitigation planning can also help allocate financial resources efficiently by identifying which facilities would benefit most from pro-active mitigation measures to reduce casualties, damages, and economic losses in future disasters. All natural hazard events pose some level of risk to facilities subject to the hazard. The level of risk varies markedly with the type and severity of hazard events and the value and vulnerability of facilities subject to the hazard.
The overall level of damage, casualties, and losses from a natural hazard event can range from none or negligible, to catastrophic events with hundreds or thousands of casualties and billions of dollars in damages and losses.
Some hazard events such as earthquakes and severe storms may affect a wide geographic area, while others such as floods and landslides typically affect relatively small geographic areas.
Some hazard events, such as earthquakes or tsunamis, may result in high damages and high casualties, while other hazard events, such as floods, may result in high damages but typically few casualties. The level of risk from natural hazards for a given facility results from the combination of hazard and exposure, as shown in the figure below.
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Figure 6.1 Hazard and Exposure Combine to Produce Risk
HAZARD EXPOSURE RISK
Frequency Value and Threat to the and Severity + Vulnerability of = Community: of Hazard Events Inventory People, Buildings and Infrastructure
Hazard Quantitative evaluation of natural hazards requires making estimates of the frequency of natural hazard events (how often they occur) as a function of the severity or size of a disaster event. All natural hazard events may occur over a wide range of severities. For example, a flood for a given campus may be several feet below the first floor of a building or several feet above the first floor. Similarly, the level of ground shaking from earthquakes affecting a campus may vary greatly, depending on the location and magnitude of earthquake events. Thus, evaluation of each natural hazard must consider events over the full range of hazard events severe enough to result in damages, losses, or casualties. The type of data necessary to evaluate natural hazards varies from hazard to hazard. Detailed guidance for each hazard is provided in Chapters 7–13, which address each of the major hazards considered in the Washington State K–12 Facilities Hazard Mitigation Plan: earthquakes, tsunamis, volcanic hazards, floods, wildland/urban interface fires, and landslides. Exposure Exposure has two elements: value and vulnerability. Value means the importance of a facility. Measures of value include the replacement value, the occupancy, and the criticality of a facility for providing services. Vulnerability means the expected extent of damages as a function of the severity of a hazard event. For example, two schools with the same level of earthquake hazard and enrollment may have the same value, but may differ markedly in their vulnerability to earthquake damage, depending on the details of their construction. In this case, the school with the higher vulnerability has the higher risk. Risk For any given hazard level, the greater the value and vulnerability, the greater the risk. Facilities with the highest level of risk are those that have both a high hazard level and a high value and vulnerability to the hazard. However, it is important to recognize that a facility with a moderate or even relatively low hazard level, but very high exposure (value and vulnerability), may well have higher risk than a similar facility with a very high hazard level but with much lower exposure. For example, an unreinforced masonry school in a moderate or even low earthquake hazard location may have a higher risk than a school recently built to current seismic design standards in a much higher earthquake hazard location.
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6.2 Natural Hazards Overview The Washington State K–12 Facilities Hazard Mitigation Plan focuses on the six natural hazards that pose the greatest risk to K–12 facilities: earthquakes, tsunamis, volcanic hazards, floods, wildland/urban interface fires, and landslides. Other natural hazards such as avalanches, droughts, and severe storms pose much lower levels of risk to K–12 facilities and thus are addressed more briefly. The important concepts for evaluating natural hazards include the following:
Some types of hazard events, such as floods, may be predicted a few hours or a few days before an event happens. There may be warnings of possible tsunamis a few minutes or a few hours before waves arrive. Hazard events such as lahars, landslides, or wildland/urban interface fires cannot be predicted in advance, but there may be generic warnings that the risk is higher than usual because of weather conditions or because a volcano is showing signs of activity. Other hazard events, such as earthquakes, have no warning (or at most a few seconds) until ground shaking starts at a given location.
Hazard events are characterized by their frequency and severity. Each type of natural hazard may occur with a very wide range of severity from barely detectable with little impact on a facility to very severe events with major impacts on a facility. A quantitative definition of the level of hazard at any given location requires making estimates of the frequency or annual probability of hazard events as a function of severity, covering the full range of possible events.
The measures of the severity of hazard events vary from hazard to hazard. For floods and tsunamis, the severity of hazard events is measured by inundation depth, along with other variables such as the flow velocity. For earthquakes, the severity at a given location is measured by the intensity and duration of ground shaking, along with the extent that secondary effects such as liquefaction or lateral spreading occur. For lahars, landslides, and wildland/urban interface fires, the severity is measured largely by the size of the affected area.
The frequency of hazard events is, by itself, not a meaningful measure of the severity of a hazard. For example, a given community may experience several winter storm events each year with generally minor to moderate impacts but may experience a major tsunami about once every 300 to 500 years on average with damages and losses in the hundreds of millions of dollars, including hundreds of deaths. The greater frequency of winter storms doesn’t mean that this hazard is of greater concern than the tsunami hazard.
Hazard analysis is inherently probabilistic. For most natural hazards, reasonable estimates of the long-term probability of future hazard events can be made as a function of the severity of hazard events, but it is impossible to predict when a major hazard event will occur in the future, other than possible very short-term warnings for some events such as floods. For example, consider a school within a FEMA-mapped 100-year floodplain. It is impossible to predict whether a 100-year flood will happen this year, next year, ten years from now, or 200 or more years from now. Some communities have experienced two or more 100-year flood events in only a few years, while others have never experienced a
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100-year flood. The correct interpretation of the likelihood of a 100-year flood at a school within a FEMA-mapped 100-year floodplain is simply that there is a one percent chance of this event, every year.
Hazard analyses provide estimates of the likelihood of future natural hazard events of varying severities, but it cannot predict when a specific hazard event will occur or how severe it will be.
A high hazard level does not, by itself, mean that there is necessarily high risk, because risk depends not only on the level of hazard but also on the value and vulnerability of facilities subject to the hazard. The above concepts apply to all natural hazards. However, as noted previously, the details vary from hazard to hazard. Detailed information about each of the major natural hazards is provided in Chapters 7–12 with brief information about other lesser natural hazards in Chapter 13.
6.3 Natural Hazards Risk Assessment, a Three-Step Process Natural hazards risk assessments can be qualitative by simply ranking the risk as high, medium, or low; or quantitative, with explicit numerical estimates of the potential for damages, losses, deaths, and injuries. The spectrum of risk assessments ranges from qualitative rankings with limited inputs of technical hazard, vulnerability, and risk data; to very detailed, rigorous quantitative assessments by engineers and natural hazards experts on a building by building basis. Purely subjective risk assessments may be very misleading and should be avoided. Both qualitative and quantitative risk assessments are useful for mitigation planning, as long as the limitations and uncertainties of both approaches are understood. The more rigorous a risk assessment is, the more accurate it will be. The cost of a more rigorous risk assessment will also be higher than for less rigorous assessment. Thus, it is not cost-effective to complete a rigorous risk assessment for every hazard for every campus or every building. The most practical, efficient, and cost-effective risk assessment approach for schools is a step- wise process which starts at the campus level then continues to the building level as outlined below. This approach helps to target the facilities with the most identifiable risk, based on the best available information. The goal of these assessments is to identify facilities that may have unacceptably high levels of risk from one or more natural hazards. They establish priorities for mitigation measures to reduce the risk so that the limited resources available for mitigation are focused effectively. The three-step hazard and risk screening approach outlined below has been incorporated into the ICOS Pre-Disaster Mitigation Database, with the interpretation of these data automated to the extent practical. Preliminary screening of natural hazards at the campus level for all K–12 facilities in Washington has been completed using statewide hazard data available from FEMA, the United States Geological Survey, the Washington Department of Natural Resources, and other agencies.
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Step One: Preliminary Screening for Hazards of Concern In many cases, it is possible to screen the major natural hazards and determine if the risk posed to a given campus by some of the hazards is nonexistent or low enough to not be of concern. Such hazard-exclusion screening is important, because it allows attention to be focused on the hazards that pose the most significant risks. However, hazard-exclusion screening must be done carefully to avoid dismissing hazards that may actually pose significant threats to a campus. If there is any doubt about excluding a given hazard from consideration when screening a campus, it is better not to exclude the hazard from consideration and to move on to Step Two of the Natural Hazards Risk Assessment. The hazard data and the hazard and risk screening is based predominantly on hazard mapping to determine which facilities are within mapped hazard areas for each of the natural hazards. Successfully completing a preliminary screening will assist districts to focus their efforts and resources on gathering more detailed data for campuses and buildings that are most likely to have the highest levels of risk. Chapters 7–12 of this plan contain more complete technical details of each hazard’s characteristics. They include a preliminary campus-level hazard screening for six major hazards. The screening is based on available statewide data. The Inventory and Condition of Schools (ICOS) database at the Office of Superintendent of Public Instruction (OSPI) has also been pre- populated with available campus-level hazard data. The preliminary hazard and risk screening, based on available statewide data, must be interpreted as the starting point for further analyses on a campus-specific or building-specific basis and not as a final determination of the estimated risk.
Step Two: Campus-Level Risk Assessments For campuses where the hazard level has been identified as being high enough to warrant a risk assessment to obtain a more accurate understanding of the risk, the next step is to refine the hazard data with campus-specific data, and combine the hazard data with campus building inventory data. As noted previously, the statewide hazard data that is available has been preloaded into the Inventory and Condition of Schools Database (ICOS) at OSPI. However, for campus-level risk assessments, it is necessary to verify the accuracy of some of the statewide data, which may be of lower resolution and lower accuracy than campus-specific data. This step also requires obtaining additional campus-specific data. Detailed guidance and templates for risk assessments are provided in the Mitigation Planning Toolkit. The brief summaries below are intended only as an introduction to the data and approaches necessary for risk assessments. Please refer to the Mitigation Planning Toolkit for further details.
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Examples of the types of campus-specific hazard data necessary for a robust risk assessment include:
Documentation of past hazard events affecting a campus.
Campus elevation data for campuses within or near flood, lahar, or tsunami inundation zones.
Quantitative flood hazard data from FEMA Flood Insurance Studies and Flood Insurance Rate Maps for campuses within FEMA-mapped floodplains.
Distances and routes for evacuation to designated safe locations for tsunami, lahar, and wildland/urban interface fire events.
Evaluation of site-specific conditions bearing on wildland/urban interface fire and landslide risks.
Evaluation of site-specific soil/rock conditions for earthquake and landslide risk. Step Three: Building-Level Risk Assessments
Examples of campus-specific building inventory data include:
Buildings’ square footage, construction date, number of stories, first floor elevation, occupancy, and replacement value.
Building structural types and details (for earthquake assessments).
The extent of or lack of fire-safe construction details (for wildland/urban interface fire assessments). Campus-level risk assessments provide the foundation for evaluating risk and for developing mitigation goals and objectives. However, in most cases, physical mitigation measures are implemented on a building-by-building basis. Therefore, developing building-specific mitigation measures usually requires more detailed building-level risk assessments. Building-level risk assessments typically require building evaluations by experts such as engineering with substantial experience with the hazard of concern. Examples where engineering evaluations are required include:
Detailed seismic evaluation of a building to identify specific structural and nonstructural seismic deficiencies, determine what retrofit measures are required and develop at least a conceptual retrofit scheme and preliminary cost estimate.
Detailed seismic and tsunami evaluation to determine if a building, with more than one story, has adequate strength to serve as a vertical evacuation shelter for tsunamis in locations where there is no high ground reachable within the available warning time.
Geotechnical studies to evaluate the level of landslide risk or the potential for liquefaction, settlement, or lateral spreading during earthquakes.
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Evaluation of the level of wildland/urban fire risk and the vulnerability of a building to fire.
Quantitative evaluation of flood risk, outside of FEMA-mapped floodplains, where special situations exist such as campuses protected by levees, dams, or reservoirs upstream from the campus. Further technical information and guidance is contained in the hazard specific chapters (chapters 7– 13) and in the Mitigation Planning Toolkit. Campus-level and building-level hazard and risk assessments for each of the six major hazards (earthquakes, tsunamis, volcanic events, floods, wildland/urban interface fires, and landslides have been incorporated into the ICOS Pre-Disaster Mitigation Database. ICOS includes statewide GIS data layers and step-by-step guidance to facilitate entry of building-specific data. The process has been simplified and automated to the extent practicable and ICOS includes exportable report tables at both the campus-level and building-level. The ICOS hazard and risk methodology is summarized in the flow chart on the following page.
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Figure 6.2 ICOS Hazard and Risk Assessment Approach
Schematic Flow Chart for ICOS Hazard and Risk Assessment Approach
District-Provided Information to Automated Screening to Identify Identify Other Hazards that May Hazards Clearly Posing Pose Significant Risk to the Significant Risk to the District District
Final List of Hazards For Which Hazard and Risk Assessments are Necessary
Automated Inputs from Campus Level Hazard and Risk District-Provided ICOS GIS Data and Assessments Data Inputs Interpretations
Automated Inputs from Building Level Hazard and Risk District-Provided ICOS from GIS Data and Assessments Data Inputs Interpretations
District's Prioritized District Criteria, Judgment Mitigation Measures and Inputs
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6.4 Evaluating Acceptable Risk The risk assessments outlined above provide the foundation for decision making and provide much of the information necessary to answer key questions about risk and mitigation priorities including:
Is the level of risk for a given campus or buildings acceptable or tolerable?
If not, what are the mitigation alternatives, and how do we choose between them? After completing the risk assessments, decision making should determine whether the level of risk from one or more natural hazards is acceptable. Acceptable risk is a concept that makes many people uncomfortable. However, there is almost always some residual risk regardless of how well a building is designed. For example:
A building where the first floor is several feet above the 100-year flood elevation may still have flood damages in a flood event much larger than a 100-year flood.
A building designed to current seismic design requirements may still have significant damage in an earthquake with higher levels of ground shaking than the design basis.
A building outside of mapped tsunami or lahar inundation zones may be inundated by tsunami or lahar events larger than anticipated. There are no universally-accepted definitions of acceptable risk. The level of risk deemed acceptable (or at least tolerable) is up to each district to determine based on the importance of each facility and on each district’s priorities. In general qualitative terms, risk may be acceptable if the expected damages are low for infrequent events and/or very low for frequent events. The higher and more frequent the expected damages are, the less likely the risk is acceptable. For example, damages of a few hundred or a few thousand dollars in minor flood events that happen every few years may be acceptable, but damages of $500,000 or $5,000,000 every few years wouldn’t be acceptable. Life safety risk, i.e. the likelihood of deaths or injuries, is almost universally deemed less acceptable than the risk of damages. For example, consider a school that, based on a risk assessment, is likely to have significant damage in a tsunami or earthquake event with a return period of about 500 years. Damage to a school once every 500 years may be acceptable, but 50 or 500 deaths once every 500 years on average is not acceptable. For K–12 facilities, high levels of risk for damages, other economic losses, or casualties may all be deemed unacceptable. However, life safety risk is generally the highest concern and mitigation to reduce life safety risk is often deemed to be the highest priority. A common mistake in mitigation planning is to focus too much on frequent hazard events with generally minor consequences and not enough on less frequent events (longer return periods) with very large or even catastrophic consequences. On the other hand, focusing too much on hazard events which are very infrequent may also be misguided.
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Natural hazard events with relatively long return periods such as a 100-year flood or a 500-year tsunami or earthquake event are often seen as rare, very unlikely events. In reality, the probability that such events occur over the next 30 or 50 years is relatively high. The following table shows the probability that natural hazard events with a wide range of return periods occur over the next 1, 10, 30, or 50 years.
Table 6.1 Probabilistic Risk Table
Return Probability of Occuring in Various Time Periods period (years) 1 Year 10 Years 30 Years 50 Years
5 20.00% 89.26% 99.88% 100.00% 10 10.00% 65.13% 95.76% 99.48% 25 4.00% 33.52% 70.61% 87.01% 50 2.00% 18.29% 45.45% 63.58% 100 1.00% 9.56% 26.03% 39.50% 200 0.50% 4.89% 13.96% 22.17% 250 0.40% 3.93% 11.33% 18.16% 500 0.20% 1.98% 5.83% 9.53% 1,000 0.10% 1.00% 2.96% 4.88% 2,500 0.04% 0.40% 1.19% 1.98% 5,000 0.02% 0.20% 0.60% 1.00% 10,000 0.01% 0.10% 0.30% 0.50% Natural hazard events with return periods may seem very long, such as 100 or 500 or 1,000 years have significant probabilities of occurring during the lifetime of a building:
Hazard events with return periods of 100 years have probabilities of occurring in the next 30 or 50 years of about 26 percent and about 40 percent, respectively.
Hazard events with return periods of 500 years have about a six percent and about a ten percent chance of occurring over the next 30 or 50 years, respectively.
Hazard events with return periods of 1,000 years have about a three percent chance and about a five percent chance of occurring over the next 30 or 50 years, respectively. That is, even events with a return period of 1,000 years (or more) may be significant if the consequences of the event happening are very severe (extremely high damages and/or substantial loss of life). For life safety considerations, even natural hazard events with very long return periods of more than 1,000 years are often deemed significant. For example, the seismic design requirements for new construction are based on the level of ground shaking with a return period of 2,475 years (two percent probability in 50 years). Providing life safety for this level of ground shaking is deemed necessary for seismic design of new buildings to minimize life safety risk.
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Of course, a hazard event with a relatively long return period of 100 years, 500 years, 1,000 or years or longer may occur tomorrow, next year, or within a few years. Return periods of 100 years, 500 years or 1,000 years mean that such events have a one percent, a 0.2 percent or a 0.1 percent chance of occurring in any given year. The most rigorous, quantitative determination of risk to a given facility, from a specified natural hazard, is to calculate the “expected average annual damages and losses.” The term “expected average annual damages and losses” means the average damages and losses considering the full range of damaging natural hazard events. For example, consider a hazard event that occurs about once per year with $1,000 in damages and a larger hazard event that occurs about every 100 years with $100,000–both contribute $1,000 to the expected average annual damages and losses. Expected average annual damages and losses are a statistical or a probabilistic estimate of the average losses expected over a long time period concluded by considering the full range of hazard events and weighting each event by the probability of occurrence. In mathematical terms, expected average annual damages and losses are obtained by integrating the probability-damage relationship for the facility for the specified natural hazard. Interpretation of expected average annual damages and losses is straightforward. For example, if the expected annual damages and losses from floods (or earthquakes or any other natural hazard) for one building are $100,000 and $200,000 for another building, then the level of risk for the second building is twice that for the first building. Expected average annual damage and loss calculations can also include estimated casualties (deaths and injuries) to provide a quantitative measure of the relative life safety risk from a group of buildings. Expected average annual damage and loss estimates can be made by using the FEMA Benefit- Cost Analysis software or using the Washington Benefit-Cost Analysis Tool (for earthquakes only) which is discussed in more detail in the Mitigation Planning Toolkit. The benefits of a mitigation project are proportional to the reduction in average annual damages and losses–that is, the difference in average annual damages between the as-is (before mitigation) and the after mitigation condition of a building. In evaluating risk for a given facility, it is important to recognize that many facilities have risk from more than one natural hazard. In this case, each of the hazards posing significant risk must be evaluated. For example, a seismic retrofit for a building with a high risk from floods or tsunamis may not make sense.
6.5 Establishing Mitigation Priorities The first step in establishing mitigation priorities is to define the relative importance of measures to reduce life safety risk versus the risk of damages and economic losses. If life safety is the highest priority, then mitigation measures that address the facilities for which the life safety risk is highest become the highest mitigation priorities. The following discussion focuses on life safety mitigation, as an example, but similar principles apply for mitigation projects to reduce damages or other economic losses.
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If a district has several schools with identified life safety risks, such as schools in mapped tsunami inundation zones or schools with significant seismic vulnerabilities, then presumably the school with the highest life safety risk is the highest priority for mitigation. The most quantitative, rigorous way to compare life safety risk for a population of schools is to calculate what is known as the “expected average annual casualty rates.” In this context, expected average annual means the average number of deaths and injuries per year over a very long time period. Expected average annual estimates require estimating the expected number of casualties as a function of the probability and severity of hazard events and then mathematically integrating the curve to determine the expected average casualty rates. Such calculations can be done using the FEMA benefit-cost software or using the Washington Benefit-Cost Analysis Tool (for earthquakes only) which is discussed in the following section. When such calculations are done, the interpretation of the results is easy: the school that has the highest expected average annual casualty rates has the highest life safety risk. Therefore, it is likely to be the highest priority for mitigation. That is, a school with an expected average annual death rate of 0.15 per year (that is 15 deaths per 100 years, on average) from earthquakes, has a higher life safety risk than one with an expected average annual death rate of 0.05 (that is, 5 deaths per 100 years, on average). Simpler, semi-quantitative analysis of relative life safety risk can be based on occupancy only if the hazard levels and vulnerability of schools are approximately equal. That is, the school with the highest occupancy probably poses the greatest life safety risk. However, because mitigation costs are generally proportional to the size of a facility, a better measure of relative risk might be the occupancy per 1,000 square feet. There are other complexities that affect prioritization of mitigation implementation, such as limited financial resources that may result in selecting the best mitigation project within available resources which may not necessarily be the highest priority project overall. However, it is important to remember that risk arises from the combination of hazard and exposure. A lower occupancy school may have higher life safety risk than a high occupancy school with the same hazard level, if the lower occupancy school has much higher vulnerability – such as the probability of collapse in an earthquake. Once a facility has been determined to be a high priority for mitigation, there is one more question to answer before exploring mitigation alternatives. Does it make more sense to replace an at-risk facility with a new facility or to mitigate the existing facility? There are several situations where replacement of an at-risk facility with a new facility may be preferable to implementing mitigation measures for an existing facility:
Mitigation costs for the existing facility are a high percentage of the cost of replacement with a new facility.
The existing facility is in poor condition, functionally obsolete, or is in a less than optimum location.
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The existing facility is subject to more than one hazard. For example, it may well not make sense to undertake a seismic retrofit for a school that is also at significant risk from floods, tsunamis, or other natural or anthropogenic (human-caused) hazards. Replacement with a new, current code facility is a very effective mitigation measure, because a new facility would be built to current building code requirements and located in conformance with floodplain management regulations and other land use regulations. However, the availability of resources to replace a building must be considered in making such a determination. Of course, with any new facility it makes sense to avoid locating the new facility in an area subject to natural or anthropogenic hazards even if building in a hazardous location would not be prohibited by existing regulations or policies. There are many factors to consider in decision making about acceptable risk and establishing mitigation priorities, including not only the potential for damages, losses, and casualties, but also factors such as:
Historical preservation. A building of historical significance may be deemed more important than a non-historic building.
Emergency shelters. Schools that are designated emergency shelters may be deemed more important than schools not so designated.
Functionality/operability for district function. A building that serves a unique function or a facility that is the only one of its kind (such as the only high school) in a district may be deemed more important than facilities where there are several such facilities in the district. The conceptual steps in decision making about acceptable risk and establishing mitigation priorities are outlined in the figure on the following page.
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Figure 6.3 The Hazard Mitigation Planning Process Flowchart
Risk Assessment Quantify the Threat to the Built Environment
Is the Level of Risk Acceptable?
YES: Risk is Acceptable, NO: Risk is Not Acceptable -Mitigation Not Necessary -Mitigation Desired
-Identify Mitigation Alternatives -Find Solutions to Risk
-Prioritize Mitigation Alternatives -Use Benefit Cost Analysis and Related Tools
-Obtain Funding -Implement Mitigation Measures -Reduce Risk
6.6 Implementing Mitigation Measures Once a school district has made a decision that mitigation is desired for a given campus or a given building, and that replacement with a new facility is not feasible, the next step is to evaluate mitigation alternatives. For any facility and any hazard there is almost always a range of possible mitigation alternatives with a wide range of cost and effectiveness in reducing future casualties, damages, and economic losses.
Developing and evaluating mitigation alternatives for a specific facility generally requires engineering and facility planning input to carefully consider the site-specific details of the hazard(s) for which a facility is being mitigated. This is needed to determine what measures are practical, and to explore the inevitable trade-off between mitigation project cost and the effectiveness of the project to reduce future disaster impacts.
Selection of a specific mitigation project, from a range of alternatives, may be made subjectively by selecting the alternative that “feels” best or may be based on cost considerations. For example, if a given alternative is the maximum cost that a district can afford, then more-robust
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A rigorous, quantitative evaluation of mitigation alternatives for a given facility can be completed via benefit-cost analysis. Benefit-cost analysis may be desired when there are two or more attractive mitigation alternatives and the selection between the alternatives is difficult. More detailed guidance on benefit-cost analysis is included in the Mitigation Planning Toolkit. The summary below focuses on how the results of benefit-cost analysis can be used to evaluate mitigation alternatives.
The results of benefit-cost analyses of mitigation projects include explicit numerical estimates of the dollar amounts for damages and economic losses and (for hazards that pose significant life safety risk) the numbers of casualties for the full range of severity of hazard events. Such results are present, both for the before-mitigation (as-is) condition of the facility and the after-mitigation condition of the facility, for a range of hazard events of various return periods and severities.
These quantitative results provide powerful insights that are helpful for decision making including:
The benefit-cost ratio for each alternative and thus whether a given alternative is eligible for possible FEMA grant funding.
The effectiveness of each alternative in reducing casualties, damages, and losses, including the residual risks after mitigation.
The trade-off between cost and performance (extent of reductions in casualties, damages, and losses).
The incremental benefits, costs, and benefit-cost ratio in going from a less expensive project to a more expensive project.
Examples of how such data may support decision making include:
Determining that a lower-cost alternative does (or does not) reduce casualties, damages, and losses to an acceptable level.
Determining that the extra costs of a higher-cost alternative reduces casualties, damages, and losses by enough to more than the lower-cost alternative to justify (or not) the higher costs.
Once a final decision has been reached on the final scope and cost of a desired mitigation project, the final steps are to obtain funding and implement the project. Mitigation projects may be funded entirely by district funding sources including capital budgets and/or bond funding or funded in part by FEMA or other grants. The Mitigation Planning Toolkit contains additional information about potential grant funding sources for mitigation projects.
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As noted previously, all FEMA mitigation grants require a benefit-cost analysis with a benefit- cost ratio of at least 1.0 for funding eligibility. Thus, benefit-cost analyses should be a part of the mitigation project development process whenever seeking FEMA grant funding.
Further information about each of the natural hazards considered in the Washington State K–12 Facilities Hazard Mitigation Plan is provided in the hazard-specific chapters which follow. These chapters also include examples of typical mitigation projects for each of the natural hazards.
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Chapter Seven: Earthquakes
7.1 Introduction Every location in Washington State has some level of earthquake hazard. However, the level of earthquake hazard varies widely according to location within the state. Historically, awareness of seismic risk in Washington has generally been high among the public and public officials. The Puget Sound area had damaging earthquakes in 1909, 1939, 1946, 1949, 1965 and 2001. Eastern Washington had damaging earthquakes in 1872 near Lake Chelan and in 1936 near Walla Walla. Epicenters of historical earthquakes in Washington with magnitudes of 3.0 or higher are shown in Figure 7.1 on the following page. The awareness of seismic risk in Washington has increased because of recent devastating earthquakes and tsunamis in Indonesia (2004) and Japan (2011). The geologic settings for the Indonesia and Japan earthquakes are very similar to the Cascadia Subduction Zone along the Washington coast.
7.2 Washington Earthquakes Earthquakes are described by their magnitude (M) which is a measure of total energy released by an earthquake. The most common magnitude is the “moment magnitude” that is calculated by seismologists from the amount of slip (movement) on the fault causing the earthquake and the area of the fault surface that ruptures during the earthquake. Moment magnitudes are similar to the Richter magnitude that was used for many decades but has now been replaced by the moment magnitude. The magnitudes for the largest earthquakes recorded worldwide and in Washington are shown below.
Table 7.1 Largest Recorded Earthquakes1, 2
Worldwide Magnitude Washington Magnitude 1960 Chile 9.5 1872 Chelan 6.8a 1964 Prince William Sound, Alaska 9.2 1949 Olympia 6.8 2004 Sumatra, Indonesia 9.1 2001 Nisqually 6.8 2011 Japan 9.0 1965 Tacoma 6.7 1952 Kamchatka, Russia 9.0 1939 Bremerton 6.2 2010 Chile 8.8 1936 Walla Walla 6.1 1906 Ecuador 8.8 1909 Friday Harbor 6.0
a Estimated magnitude.
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Figure 7.1 Epicenters of Historic Earthquakes in Washington with Magnitudes of 3.0 or Higher3
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Table 7.1 and Figure 7.1 do not include the January 26, 1700 earthquake on the Cascadia Subduction Zone which has been identified by tsunami records in Japan and paleoseismic investigations along the Washington Coast. The estimated magnitude of the 1700 earthquake is approximately 9.0. This earthquake is not shown in Table 7.1 because it predates modern seismological records. However, this earthquake is among the largest known earthquakes worldwide and the largest earthquake affecting Washington over the past several hundred years. The closest analogy to this earthquake and its effects, including tsunamis, is the 2011 Japan earthquake. Earthquakes in Washington, and throughout the world, occur predominantly because of plate tectonics–the relative movement of plates of oceanic and continental rocks that make up the rocky surface of the earth. Earthquakes can also occur because of volcanic activity and other geological processes. The Cascadia Subduction Zone is a geologically complex area off the Pacific Northwest Coast from Northern California to British Columbia. In simple terms, several pieces of oceanic crust (the Juan de Fuca Plate and other smaller pieces) are being subducted (pushed under the crust) in North America. This subduction process is responsible for most of the earthquakes in the Pacific Northwest and for creating the volcanoes in the Cascades. Figure 7.2 on the following page shows the geologic (plate-tectonic) setting of the Cascadia Subduction Zone. There are three main source regions for earthquakes that affect Washington. They are 1) “Interface” earthquakes on the boundary between the subducting oceanic plates and the North American plate, 2) “Intraplate” earthquakes within the subducting oceanic plates, and 3) “Crustal” earthquakes within the North American Plate. “Interface” earthquakes on the Cascadia Subduction Zone occur on the boundary between the subducting plate and the North American Plate and may have magnitudes up to 9.0 or perhaps 9.2, with probable return periods (the time period between earthquakes) of 300 to 500 years. These are the great Cascadia Subduction Zone earthquake events that have received attention in the popular press. The last major interface earthquake on the Cascadia Subduction Zone occurred on January 26, 1700. These earthquakes occur about 40 miles offshore from the Pacific Ocean Coastline. Ground shaking from such earthquakes would be the strongest near the coast, and strong ground shaking would be felt throughout much of Western Washington with the level of shaking decreasing further inland from the coast.
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Figure 7.2 Cascadia Subduction Zone4
Paleoseismic investigations have identified 41 Cascadia Subduction Zone interface earthquakes over the past 10,000 years. This history corresponds to one earthquake about every 250 years. Of these 41 earthquakes, about half are M9.0 or greater that represent full rupture of the fault zone from Northern California to British Columbia. The other half of the earthquakes represents M8+ earthquakes that rupture only the southern portion of the subduction zone. The 300+ years since the last major Cascadia Subduction Zone earthquake is longer than the average of about 250 years for M8 or greater and shorter than some of the intervals between M9.0 earthquakes. The time history of these major earthquakes is shown below.
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Figure 7.3 Time History of Cascadia Subduction Zone Interface Earthquakes5
“Intraplate” earthquakes occur within the subducting oceanic plate. These earthquakes may have magnitudes up to about 7.5 with probable return periods of about 500 to 1000 years at any given location. These earthquakes can occur anywhere along the Cascadia Subduction Zone. The 1949, 1965, and 2001 earthquakes listed in Table 7.1 are examples of this type of earthquake. These earthquakes occur deep in the earth’s crust, about 20 to 30 miles below the surface. They generate strong ground motions near the epicenter but have damaging effects over significantly smaller areas than the larger magnitude interface earthquakes discussed above. “Crustal” earthquakes occur within the North American plate. Crustal earthquakes are shallow earthquakes, typically within the upper five or ten miles of the earth’s surface, and some ruptures may reach the surface. In western Washington, crustal earthquakes are mostly related to the Cascadia Subduction Zone. In central and eastern Washington, the mechanisms responsible for crustal earthquakes are not as well understood and may be related to the Cascadia Subduction Zone and/or to other geological/tectonic processes. There are numerous crustal faults mapped within Washington State. USGS-mapped faults in the Puget Sound Area are shown in Figure 7.4 and listed in Table 7.2.
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Figure 7.4 USGS Mapped Crustal Faults in the Puget Sound Area 6,7
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Table 7.2 USGS Mapped Faults in the Puget Sound Area6, 7
Fault Number Fault Name 550 Calawah Fault 551 Unnamed Faults In Straight of Juan de Fuca 552 Hood Canal Fault Zone 554 Macaulay Creek Fault 555 Unnamed Fault South of Port Angeles 556 Little River Fault 557 Unnamed Fault along Barnes Creek 570 Seattle Fault Zone 571 Strawberry Fault Zone 572 Southern Whidbey Island Fault 573 Utsalady Point Fault 574 Devils Mountain Fault 575 Saddle Mountain Faults
581 Tacoma Fault Zone
USGS-mapped faults in the Walla Walla area are shown in Figure 7.5 and listed in Table 7.3. This figure is shown as an example of active faults in eastern Washington. USGS-mapped faults elsewhere in Washington are shown on an interactive map of mapped faults in the United States. Faults within Washington can be seen by zooming in using the “+” button in the upper left corner, and then scrolling to WA State. Additional data about each fault can be obtained by clicking on the trace of the fault on the map at http://earthquake.usgs.gov/hazards/qfaults/map/.
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Figure 7.5 USGS Mapped Faults in the Walla Walla Area8
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Table 7.3 USGS Mapped Faults in the Walla Walla Area8
Fault Number Fault Name
561a,b,c Frenchman Hills Faults and Structuresa 562a,b Saddle Mountain Faults and Structures 563a,b Umtanum Ridge Faults and Structures 565 Rattlesnake Hills Structures 567 Horse Haven Hills Structures 578a,b Faults Near Walla Walla 696 Thompson Valley Fault 698 Jocko Fault 699a,b Mission Fault 705 Ninemile Fault 845a,b Hite Fault System 846 Wallula Fault System a The geologic term "structure" means folds and other geologic structures deemed capable of generating earthquakes.
Fault zones and seismogenic fold zones in Washington, that are known to be active, or suspected of being active, by the Washington State Department of Natural Resources, are shown in Figure 7.6.
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Figure 7.6 Faults and Seismogenic Folds in Washington Known or Suspected to be Active3
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Crustal earthquakes are possible not only on faults mapped as active or potentially active but also on unknown faults. Many significant earthquakes in the United States have occurred on previously unknown faults. Based on the historical seismicity in Washington and on analogies to other geologically similar areas, small to moderate crustal earthquakes up to M5 or M5.5 are possible almost any place in Washington. There is also a possibility of larger crustal earthquakes in the M6+ range; albeit, in the absence of known mapped faults, the probability of such events is likely to be low.
7.3 Earthquake Concepts for Risk Assessments
Earthquake Magnitudes When evaluating earthquakes, it is important to recognize that the earthquake magnitude scale is not linear but rather logarithmic. Each one step increase in magnitude, for example from M7 to M8, corresponds to an increase of about a factor of 30 in the amount of energy released by the earthquake because of the mathematics of the magnitude scale. Thus, an M7 earthquake releases about 30 times more energy than an M6, while an M8 releases about 30 times more energy than an M7 and so on. Thus, a great M9 earthquake releases nearly 1,000 times more energy than a large earthquake of M7 and nearly 30,000 times more energy than an M6 earthquake. The public often assumes that the larger the magnitude of an earthquake, the “worse” it is. That is, the “big one” is the M9 earthquake and smaller earthquakes such as M6 or M7 are not the “big one”. This is only true in very general terms. Higher magnitude earthquakes do affect larger geographic areas with much more widespread damage than smaller magnitude earthquakes. However, for a given site, the magnitude of an earthquake is not a good measure of the severity of the earthquake at that site. For any earthquake, the intensity of ground shaking at a given site depends on four main factors:
Earthquake magnitude.
Earthquake epicenter, which is the location on the earth’s surface directly above the point of origin of an earthquake.
Earthquake depth.
Soil or rock conditions at the site, which may amplify or de-amplify (dampen) earthquake ground motions. An earthquake will generally produce the strongest ground motions near the epicenter (the point on the ground above where the earthquake initiated) with the intensity of ground motions diminishing with increasing distance from the epicenter. The intensity of ground shaking at a given location depends on the four factors listed above. Thus, for any given earthquake there will be contours of varying intensity of ground shaking versus distance from the epicenter. The intensity will generally decrease with distance from the epicenter, and often in an irregular pattern, not simply in concentric circles. This irregularity is caused by soil conditions, the
Page | 74 complexity of earthquake fault rupture patterns, and possible directionality in the dispersion of earthquake energy. The amount of earthquake damage and the size of the geographic area affected generally increase with earthquake magnitude:
Earthquakes below about M5 are not likely to cause significant damage, even locally very near the epicenter.
Earthquakes between about M5 and M6 are likely to cause moderate damage near the epicenter.
Earthquakes of about M6.5 or greater (e.g., the 2001 Nisqually earthquake in Washington) can cause major damage, with damage usually concentrated fairly near the epicenter.
Larger earthquakes of M7+ cause damage over increasingly wider geographic areas with the potential for very high levels of damage near the epicenter.
Great earthquakes with M8+ can cause major damage over wide geographic areas.
A mega-quake M9 earthquake on the Cascadia Subduction Zone could affect the entire Pacific Northwest from British Columbia, through Washington and Oregon, and as far south as Northern California with the highest levels of damage nearest the coast.
Intensity of Ground Shaking There are many measures of the severity or intensity of earthquake ground motions. The Modified Mercalli Intensity scale (MMI) was widely used beginning in the early 1900s. MMI is a descriptive, qualitative scale that relates severity of ground motions to the types of damage experienced. MMIs range from I to XII. More accurate, quantitative measures of the intensity of ground shaking have largely replaced the MMI and these are used in this mitigation plan. Modern intensity scales use parameters that can be physically measured with seismometers, such as the acceleration, velocity, or displacement (movement) of the ground. The intensity of earthquake ground motions may also be measured in spectral terms as a function of the frequency of earthquake waves propagating through the earth. In the same sense that sound waves contain a mix of low, moderate, and high-frequency sound waves, earthquake waves contain ground motions of various frequencies. The behavior of buildings and other structures depends substantially on the vibration frequencies of the building or structure versus the spectral (frequency) content of earthquake waves. Earthquake ground motions also include both horizontal and vertical components. A common physical measure of the intensity of earthquake ground shaking, and the one used in this mitigation plan, is Peak Ground Acceleration (PGA). PGA is a measure of the intensity of shaking relative to the acceleration of gravity (g). For example, an acceleration of 1.0 g PGA is an extremely strong ground motion that does occur near the epicenter of large earthquakes. With a vertical acceleration of 1.0 g, objects are thrown into the air. With a horizontal acceleration of
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1.0 g, objects accelerate sideways at the same rate as if they had been dropped from the ceiling. Ten percent g PGA means that the ground acceleration is ten percent that of gravity, and so on. Damage levels experienced in an earthquake vary with the intensity of ground shaking and with the seismic capacity of structures. The following generalized observations provide qualitative statements about the likely extent of damages for earthquakes with various levels of ground shaking (PGA) at a given site:
Ground motions of only one percent g or two percent g are widely felt by people. Hanging plants and lamps swing strongly, but damage levels, if any, are usually very low.
Ground motions below about ten percent g usually cause only slight damage.
Ground motions between about ten percent g and 30 percent g may cause minor to moderate damage in well-designed buildings with higher levels of damage in more vulnerable buildings. At this level of ground shaking, some poorly designed buildings may be subject to collapse.
Ground motions above about 30 percent g may cause significant damage in well-designed buildings and very high levels of damage (including collapse) in poorly designed buildings.
Ground motions above about 50 percent g may cause significant damage in most buildings, even those designed to resist seismic forces.
7.4 Earthquake Hazard Maps The current scientific understanding of earthquakes is incapable of predicting exactly where and when the next earthquake will occur. However, the long term probability of earthquakes is well enough understood to make useful estimates of the probability of various levels of earthquake ground motions at a given location. The current consensus estimates for earthquake hazards in the United States are incorporated into the 2008 USGS National Seismic Hazard Maps. These maps are the basis of building code design requirements for new construction, per the International Building Code adopted in Washington. The earthquake ground motions used for building design are set at 2/3rds of the two percent in 50 years level of ground motion. The following maps show contours of Peak Ground Acceleration (PGA) with ten percent and two percent chances of occurring over the next 50 years. The ground shaking values on the maps are expressed as a percentage of g, the acceleration of gravity. For example, the ten percent in 50 year PGA value means that over the next 50 years there is a ten percent probability of this level of ground shaking or higher. In very qualitative terms, the ten percent in 50 year ground motion represents a likely earthquake while the two percent in 50 year ground motion represents a level of ground shaking close to, but not the absolute, worst case scenario.
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A very important caveat for interpreting these maps is that the 2008 USGS seismic hazard maps show the level of ground motions for rock sites. Ground motions on soil sites, especially soft soil sites, will be significantly higher than for rock sites. Thus, for earthquake hazard analysis at a given site, it is essential to include consideration of the site’s soil conditions. Figure 7.6 on the following page, the statewide two percent in 50 year ground motion map, is the best statewide representation of the variation in the level of seismic hazard in Washington with location:
The dark red, pink, and orange areas have the highest levels of seismic hazard.
The tan, yellow, and blue areas have intermediate levels of seismic hazard.
The bright green and pale green areas have the lowest levels of seismic hazard. The detailed geographical patterns in the maps reflect the varying contributions to seismic hazard from earthquakes on the Cascadia Subduction Zone and crustal earthquakes within the North American Plate. For example, the bands of dark red (very high hazard) in the Puget Sound area shown in Figures 7.7 and 7.9 reflect areas with a moderately high earthquake hazard from Cascadia Subduction Zone earthquakes combined with a high hazard from the most active crustal faults in the Puget Sound Area–the Seattle Fault System and the Southern Whidbey Island Fault. The differences in geographic pattern between the two percent in 50 year maps and the ten percent in 50 year maps reflect different contributions from Cascadia Subduction Zone earthquakes and crustal earthquakes. These maps are generated by including earthquakes from all known faults, taking into account the expected magnitudes and frequencies of earthquakes for each fault. The maps also include contributions from unknown faults that are statistically possible anywhere in Washington. The contributions from unknown faults are included via “area” seismicity which is distributed throughout the state.
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Figure 7.7 2008 USGS Seismic Hazard Map: Washington State PGA value (percent g) with a Two Percent Chance of Exceedance in 50 years
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Figure 7.8 2008 USGS Seismic Hazard Map: Washington State PGA value (percent g) with a Ten percent Chance of Exceedance in 50 years
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Figure 7.9 2008 USGS Seismic Hazard Map: Puget Sound Area PGA value (percent g) with a Two percent Chance of Exceedance in 50 years
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Figure 7.10 2008 USGS Seismic Hazard Map: Puget Sound Area PGA value (percent g) with a Ten percent Chance of Exceedance in 50 years
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The ground motions shown in the previous figures represent ground motions with the specified probabilities of occurrence. At any given site, earthquakes may be experienced with ground motions over the entire range of levels of ground shaking from just detectible with sensitive seismometers to higher than the two percent in 50 year ground motion. The complete probabilistic picture of earthquake ground motions at a given site is shown in a seismic hazard curve that shows the annual probability of ground motions covering the full range of ground motions. For any site, the annual probability always decreases with increasing level of ground shaking (PGA). Figure 7.11 shows the annual probability of earthquake ground motions exceeding each level of ground shaking. For example, the annual probability of 0.40 g is a little higher than 0.0001. However, as illustrated in the preceding figures, the levels of ground shaking vary markedly with location in Washington.
Figure 7.11 Seismic Hazard Curve Example
A summary of the levels of seismic hazard is shown below in Table 7.4.
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Table 7.4 Earthquake Ground Motions with a Two Percent Chance of Being Exceeded in 50 Years
Percent of Peak Ground Number of Percent of Campuses Acceleration Campuses Campuses This Level (% g) or Higher
70% to 74% 26 1.07% 1.07%
60% to 70% 246 10.14% 11.21%
50% to 60% 913 37.63% 48.85%
40% to 50% 465 19.17% 68.01%
30% to 40% 136 5.61% 73.62%
25% to 30% 173 7.13% 80.75%
20% to 25% 215 8.86% 89.61%
15% to 20% 243 10.02% 99.63%
Less Than15% 9 0.37% 100.00%
Totals 2426 100.00% N/A
As shown in Table 7.4, 68 percent of the campuses have ground motions of 40 percent g or higher and more than 80 percent have ground motions of 25 percent g or higher, for the two percent in 50 years level of ground shaking. Ground motions in this range are likely to result in significant damage for many buildings. Only about ten percent of campuses have ground motions below 20 percent g for the two percent in 50 years level of ground shaking. Overall, the range of ground motions for the 2,426 campuses is a high of 73.99 percent g and a low of 12.52 percent g. Ground motions at the high end of this range are likely to result in significant damages even for buildings designed to current seismic codes. Ground motions towards the low end of this range may result in significant damage for a few buildings that are unusually vulnerable to earthquake damage. These ground motions are based on the USGS two percent in 50 year ground motions, as shown in Figure 7.6, adjusted for the Washington Department of Natural Resources estimates of soil and rock types for each campus location. As discussed previously and in the following section, soil sites in general, and especially soft soil sites, amplify earthquake ground motions.
7.5 Site Class: Soil and Rock Types As discussed previously, the soil or rock type at a given location substantially affects the level of earthquake hazard, because the soil or rock type may amplify or de-amplify ground motions. In general, soil sites amplify ground motions–that is for a given earthquake, a soil site immediately adjacent to a rock site will experience higher levels of earthquake ground motions than the rock
Page | 83 site. However, at very high levels of ground shaking, soft soil sites actually de-amplify ground motions rather than amplifying them. In simple terms, the six site classes are identified as follows: A – Hard Rock B – Rock C – Very Dense Soil and Soft Rock D – Firm Soil E – Soft Soil F – Very Soft Soil
For reference, the formal technical definitions of site class per the International Building Code are shown below.
Table 7.5 International Building Code Site Class Technical Definitions
Site Soil Profile Name Shear Wave Std Penetration Undrained Shear Class Velocity , Vs (ft/s) Resistance, N Strength, Su (psf)
A Hard Rock Vs > 5000 N/A N/A
B Rock 2500 < Vs ≤ 5000 N/A N/A
C Very Dense Soil & Soft Rock 1200 < Vs ≤ 2500 N > 50 Su ≥ 2000
D Stiff Soil 600 ≤ Vs ≤ 1200 15 ≤ N ≤ 50 1000 ≤ Su ≤ 2000
Soft Clay Soil Vs < 600 N < 15 Su < 1000 Any profile with more than 10 feet of soil having the following characteristics: E 1. Plasticity index PI > 20, 2. Moisture content w ≥ 40%, and
3. Undrained shear strength Su < 500 psf F Site specific soil investigation required
The Washington Department of Natural Resources (DNR) has made statewide estimates of site class based on available geological data. Site class varies markedly with location, often over very short distances. Thus, it is not possible to show site class maps except at high spatial resolution for small areas. However, the ICOS Pre-Disaster Mitigation Database at OSPI includes the DNR site class estimates for each K–12 campus in Washington. In addition to the six standard site classes shown in Table 7.4, the DNR estimates also include intermediate classifications where the available geological data are insufficient to identify the specific site class. These intermediate classifications include: B–C, C–D, and D–E.
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For risk assessment purposes, the amplification/de-amplification for sites with intermediate site classes can be interpolated or rounded up to higher of the two site class ground motions.
7.6 Ground Failures and Other Aspects of Seismic Hazards Much of earthquake damage occurs from ground shaking that affects buildings and infrastructure. However, there are several other consequences of earthquakes that can result in substantially increased levels of damage in some locations. These consequences include surface rupture, subsidence or elevation, liquefaction, settlement, lateral spreading, landslides, dam, reservoir or levee failures, tsunamis, and seiches. Any of these consequences can result in very severe damage to buildings, up to and including complete destruction, as well as a high likelihood of casualties. Surface Rupture Surface rupture occurs when the fault plane, along which rupture occurs in an earthquake, reaches the surface. Surface rupture may be horizontal and/or vertical displacement between the sides of the rupture plane. For a building subject to surface rupture, the level of damage is typically very high and generally results in destruction of the building. Horizontal or vertical rupture through a building in a major earthquake means that two parts of the building are displaced by up to several feet or more in the horizontal or vertical direction or both. Surface rupture does not occur with interface or intraplate earthquakes on the Cascadia Subduction Zone and does not occur with all crustal earthquakes. However, surface rupture does occur when crustal earthquake fault ruptures reach and break the ground surface. Faults in Washington where surface rupture is likely, include the Seattle Fault System, the Tacoma Fault System, and the Southern Whidbey Island Fault System.
Subsidence or Uplift Large interface earthquakes on the Cascadia Subduction Zone are expected to result in subsidence of up to several feet in many coastal locations, while other locations may be uplifted by several feet. For facilities located very near sea level, co-seismic subsidence may result in the facilities being below sea level or low enough so that flooding becomes very frequent. Subsidence may also impede egress by blocking some evacuation routes and thus increase the likelihood of casualties from tsunamis. Subsidence or uplift may be fairly uniform over an area or be uneven due to variations in soil/rock type. Uneven subsidence or uplift may substantially increase building damages in a manner analogous to surface rupture.
Liquefaction, Settlement, and Lateral Spreading Liquefaction is a process where loose, wet sediments lose bearing strength during an earthquake and behave similar to a liquid. Once a soil liquefies, it tends to settle vertically and/or spread laterally. With even very slight slopes, liquefied soils tend to move sideways downhill (lateral spreading). Settlement or lateral spreading can cause major damage to buildings and to buried infrastructure such as pipes and cables.
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The Washington Department of Natural Resources (DNR) has made statewide estimates of liquefaction potential, based on available geological data. Liquefaction potential varies markedly with location, often over very short distances. Thus, it is not possible to show liquefaction potential maps except at high spatial resolution for small areas. However, the ICOS Pre-Disaster Mitigation Database at OSPI includes the DNR liquefaction potential estimates for each K–12 campus in Washington with the following categories: very low, very low to low, low, low to moderate, moderate, moderate to high, high, and very high.
Landslides Earthquakes can also induce landslides, especially if an earthquake occurs during the rainy season and soils are saturated with water. The areas prone to earthquake-induced landslides are largely the same as those areas prone to landslides in general. As with all landslides, areas of steep slopes with loose rock or soils and high water tables are most prone to earthquake-induced landslides. See Chapter 12: Landslides for a more detailed discussion of landslides. Dam, Levee, and Reservoir Failures Earthquakes can also cause dam failures in several ways. The most common mode of earthquake-induced dam failure is slumping or settlement of earth fill dams where the fill has not been properly compacted. If the slumping occurs when the dam is full, then overtopping of the dam with rapid erosion leading to dam failure is possible. Dam failure is also possible if strong ground motions heavily damage concrete dams. Earthquake induced landslides into reservoirs have also caused dam failures. Earthquake-induced failures of levees are very similar to failures of earth fill dams. If levee crests slump enough to create overtopping, then rapid erosion leading to levee failure is possible. Earthquake-induced failures of concrete or steel water storage reservoirs for potable water systems are also possible. For campuses behind levees or with dams or reservoirs upstream from a campus, a seismic risk assessment should include evaluation of possible inundation of the campus from dam, levee, or reservoir failures.
Tsunamis and Seiches Tsunamis, that are sometimes incorrectly referred to as “tidal waves,” result from earthquakes that cause a sudden rise or fall of part of the ocean floor. Such movements may produce tsunami waves that have nothing to do with the ordinary ocean tides. Tsunamis may also be generated by undersea landslides, by terrestrial landslides into bodies of water, and by asteroid impacts. However, earthquakes are the predominant cause of tsunamis. In the open ocean, far from land and in deep water, tsunami waves may be only a few inches high and thus be virtually undetectable except by special monitoring instruments. These waves travel across the ocean at speeds of several hundred miles per hour. When such waves reach shallow water near the coastline, they slow down and can gain great heights.
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Tsunamis affecting the Washington Coast can be produced from very distant earthquakes off the coast of Alaska or elsewhere in the Pacific Ocean. For such tsunamis, the warning time for the Washington Coast would be at least several hours. However, interface earthquakes on the Cascadia Subduction Zone can also produce tsunamis. For such earthquakes, the warning times would be very short–less than 30 minutes for some coastal locations. Because of this extremely short warning time, emergency planning and public education about the critical importance of rapid evacuation are essential before such an event occurs. Tsunamis can also be created by crustal earthquakes, such as the Seattle Fault System and the Tacoma Fault System that cross parts of Puget Sound because these earthquakes are likely to include vertical movements of the Sound floor that will generate tsunamis. The warning times for such tsunamis would be only a few minutes. A similar earthquake phenomenon is “seiches” that are waves from sloshing of inland bodies of waters such as lakes, reservoirs, or rivers. Seiches may result in damages to docks and other shoreline, or near-shore, structures. See Chapter Eight: Tsunamis, for a more detailed discussion.
7.7 Scenario Earthquake Loss Estimates for K–12 Facilities in Washington Scenario Earthquakes There are a wide range of possible earthquakes with many different magnitudes and locations that will affect K–12 facilities, including not only Cascadia Subduction Zone earthquakes and crustal earthquakes on known faults, but also crustal earthquakes on unknown faults. To explore the range of potential earthquake impacts on K–12 facilities in Washington, we consider nine scenario earthquakes. These scenarios include the most likely major earthquakes, including “interface” and “intraplate” earthquakes on the Cascadia Subduction Zone and the most likely major crustal earthquakes on active faults such as the Seattle Fault Zone. For completeness, we also consider several lower probability earthquakes with longer return periods on mapped faults in Central and Eastern Washington.
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Table 7.6 Scenario Earthquakes
Return Period Earthquake Fault Magnitudea (Years) Cascadia Subduction Zone: Interface 9.0 500b Cascadia Subduction Zone: Intraplate (Nisqually) 7.2 500b Seattle Fault System 7.2 1,000b Southern Whidbey Island Fault System 7.4 4,000c Chelan Fault Zone 7.2 Unknown Cle Elum Seismic Zone 6.8 Unknown Mill Creek Fault Zone 7.0 40,000d Latah Fault Zone 5.5 Unknown Hite Fault Zone 6.8 140,000d a Department of Natural Resources magnitude for earthquake scenarios.
b Estimate based on historical events and paleoseismic studies.
c Calculated from USGS estimates of about 12,000 years for each of the northern, middle and southern fault zones.9
d 9 USGS estimate , rounded. Paleoseismic studies of the Cascadia Subduction Zone interface earthquakes suggest return periods varying from about 250 years to about 500 years, with about 250 years being the average for M8+ earthquakes and about 500 years being the average for M9 or greater earthquakes.9 Because the last such earthquake occurred in 1700, the annual probability of a future earthquake is probably higher than indicated by the long term averages stated above. Cascadia Subduction Zone intraplate earthquakes occurred in 1949, 1965, and 2001. The 500-year estimated return period is based on the fact that such earthquakes can occur anywhere within the subducting plate. Thus, the return period at any given location is much longer than the return period for such earthquakes on the entire subducting plate and because the M7.2 scenario is significantly larger than the historical earthquakes with M6.7 or M6.8. The USGS estimated return period for the Seattle Fault northern zone is 5,000 years with no return periods estimated for the middle and southern fault zones.10 Paleoseismic studies suggest three surface rupturing events in the past 2,500 years.11 The 1,000 year return period estimate assumes that return periods for the middle and southern fault zones is similar to that for the northern zone and combines this with the estimate of three events in 2,500 years. HAZUS Loss Estimates for Scenario Earthquakes FEMA’s HAZUS MH Version 2.1 software was used to estimate the casualties, damages, and economic losses for K–12 facilities for each of the nine scenario earthquakes.
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These estimates are based on available statewide data and estimates and should not be interpreted literally but rather as approximate estimates of the levels of casualties, damages, and economic losses likely if each of these scenario earthquakes were to occur. These results should be interpreted in the aggregate only–at the statewide level or county level–and not interpreted at the district or campus level. Making credible loss estimates at the district or campus level requires much more detailed district-level, campus-level, and building-level data than was available for these scenarios. Data inputs for these earthquake scenarios include:
USGS shakemaps with earthquake ground motions for each scenario.
Total square footage of buildings at each campus.
The number of portable buildings at each campus.
In the absence of detailed data on building types for each K–12 building, the total square footage of non-portable buildings was estimated as follows: o Wood frame (77 percent). o Masonry (12 percent). o Steel (8 percent). o Concrete (3 percent).
Structural building types for non-wood frame buildings were allocated per HAZUS default assumptions.
Estimated average occupancies per 1,000 square feet during school hours: o High Schools – 7. o Middle Schools – 7.5. o Elementary Schools and Others – 10.
Building replacement values per square foot: o High Schools – $277.20. o Middle Schools – $316.50. o Elementary Schools and Others – $272.99. o Portables – $95.00.
Contents value–an average of 5.22 percent of building replacement value. Estimated values for elementary, middle, and high schools are $10/SF, $14/SF, and $19/SF, respectively, from insured replacement values.
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Seismic vulnerability parameters–HAZUS default assumptions. HAZUS results for the nine scenario earthquakes are summarized in the tables which follow. Building and contents damages are based on typical replacement values for buildings and contents and HAZUS estimated damage percentages as a function of level of ground shaking. Estimate numbers of injuries and deaths are based on the estimated average occupancies for schools and HAZUS estimates of casualties as a function of building damage:
Level One – Minor Injuries.
Level Two – Major Injuries.
Level Three – Critical Injuries that pose an immediate life threatening condition if not treated immediately. Many persons with this level of injury may die.
Level Four – Death Business Interruption Costs include displacement costs to temporary facilities, disruption costs, income loss, and wage losses. These estimates are based entirely on HAZUS values:
Income Losses: $0.146 per square foot per day.
Wage Losses: $0.345 per square foot per day.
Rental Costs: $0.051 per square foot per day.
Disruption Costs: $0.95 per square foot per day. Actual values may differ from the above HAZUS values and may vary from district to district and earthquake event to earthquake event. CAVEAT Re: Interpretation of HAZUS Results The HAZUS results on the following pages are based on available statewide data and estimates. There is significant uncertainty in earthquake damage and loss estimates. The numerical results should not be interpreted literally as predictions for any scenario earthquake but rather as approximate estimates of the level of possible damages, losses, and casualties. Actual damages, losses, and casualties in future earthquakes may be significantly higher or lower than these estimates.
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Table 7.7 Summary of HAZUS Scenario Earthquake Results: K–12 Facilities Statewide
Business Total Building Building Contents Contents Scenario Earthquake Interruption Damages Damages Loss Ratio Damages Loss Ratio Losses and Losses Cascadia Subduction Zone: Interface M9.0 $2,275,193,858 5.0% $45,300,454 1.9% $1,767,967,467 $4,088,461,779 Cascadia Subduction Zone: Intraplate M7.2 $518,208,330 1.1% $18,426,448 1.1% $626,106,684 $1,162,741,462 Chelan Fault Zone M7.2 $79,517,226 0.17% $2,031,801 0.08% $52,248,796 $133,797,823 Cle Elum Seismic Zone M6.8 $38,129,250 0.08% $1,110,788 0.05% $38,008,508 $77,248,546 Hite Fault Zone M6.8 $62,388,034 0.14% $1,665,298 0.07% $31,428,547 $95,481,879 Latah Fault Zone M5.5 $29,679,735 0.06% $1,316,763 0.60% $40,870,903 $71,867,401 Mill Creek Fault Zone M7.0 $66,240,443 0.14% $1,941,627 0.08% $56,771,629 $124,953,699 Seattle Fault System M7.2 $2,861,645,684 6.2% $57,913,146 2.4% $2,518,588,387 $5,438,147,217 Southern Whidbey Island Fault System M7.4 $1,750,506,069 3.8% $36,435,231 1.5% $1,405,060,608 $3,192,001,908
Critical Major Minor Total Deaths Scenario Earthquake Deaths Injuries Injuries Injuries and Injuries Cascadia Subduction Zone: Interface M9.0 117 60 507 2,543 3,227 Cascadia Subduction Zone: Intraplate M7.2 5 2 41 353 401 Chelan Fault Zone M7.2 4 2 16 75 97 Cle Elum Seismic Zone M6.8 1 0 4 27 32 Hite Fault Zone M6.8 6 3 21 85 115 Latah Fault Zone M5.5 0 0 1 14 15 Mill Creek Fault Zone M7.0 2 1 10 60 73 Seattle Fault System M7.2 255 130 995 4,034 5,414 Southern Whidbey Island Fault System M7.4 136 70 549 2,318 3,073
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The estimated casualties for the scenario earthquake shown above are for school occupancies (students and staff) during normal school hours when schools are in session. These casualty estimates are based on the simplified assumptions in HAZUS which assume “typical” seismic performance of buildings of a given structural type. Actual casualties may be higher:
In many earthquakes, a majority of casualties occur from a few buildings that have major damage and collapse.
The possible collapse of even a few more school buildings could result in much higher casualties than shown above.
Many people with critical injuries will die.
These results do not include deaths and injuries from tsunamis that are expected from the Cascadia Subduction Zone M9.0, Seattle Fault Zone M7.2, and the Southern Whidbey Island M7.4 earthquake scenarios. Detailed results for the Cascadia M9.0 scenario earthquake are shown in Table 7.8 and Figure 7.12. The casualty estimates in Table 7.8 have fractional deaths and injuries, which are shown to avoid rounding errors and to avoid showing zero casualties when a small number are expected statistically. These fractional casualties are interpreted probabilistically. For example, the 0.6 deaths in Whatcom County schools should be interpreted as a 60 percent chance of one death. The full set of detailed results tables and maps for all of the earthquake scenarios are included in the Appendices.
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Table 7.8 Cascadia Subduction Zone Interface M9.0 Scenario
Minor Major Critical Building Contents County # Schools Max PGA Deaths Building Loss ($) Content Loss ($) BI Loss ($) Total Loss ($) Injuries Injuries Injuries Loss (%) Loss (%) Adams 12 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Asotin 12 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Benton 60 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Chelan 38 0.08 0.5 0.0 0.0 0.0 $1,069,641 0.2% $47,643 0.1% $103,485 $1,220,768 Clallam 35 0.40 130.1 31.3 4.2 8.2 $97,320,773 18.3% $1,789,477 6.5% $71,393,867 $170,504,118 Clark 130 0.20 76.3 12.5 1.3 2.5 $75,980,726 2.8% $2,102,313 1.5% $74,414,718 $152,497,757 Columbia 4 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Cowlitz 46 0.24 68.3 15.9 2.3 4.4 $51,511,029 6.0% $1,293,987 2.9% $40,597,064 $93,402,080 Douglas 20 0.08 0.3 0.0 0.0 0.0 $474,996 0.1% $16,938 0.1% $0 $491,934 Ferry 13 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Franklin 28 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Garfield 2 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Grant 54 0.08 0.1 0.0 0.0 0.0 $278,020 0.0% $9,984 0.0% $0 $288,005 Grays Harbor 44 0.44 232.1 64.5 9.9 19.4 $149,301,048 20.7% $3,602,928 9.6% $160,233,874 $313,137,849 Island 23 0.20 25.6 4.5 0.5 0.9 $27,044,566 6.1% $514,426 2.2% $23,415,290 $50,974,281 Jefferson 15 0.40 20.9 4.1 0.5 0.9 $18,676,178 8.5% $378,390 3.3% $11,899,887 $30,954,455 King 558 0.24 730.8 131.4 13.8 27.0 $703,590,293 6.1% $13,102,855 2.2% $559,874,105 $1,276,567,252 Kitsap 82 0.28 120.0 22.0 2.3 4.5 $116,045,290 7.2% $2,353,435 2.8% $87,042,552 $205,441,277 Kittitas 19 0.08 1.2 0.1 0.0 0.0 $1,875,705 0.6% $60,212 0.3% $1,344,315 $3,280,233 Klickitat 22 0.08 0.4 0.0 0.0 0.0 $634,336 0.2% $18,853 0.1% $118,635 $771,824 Lewis 43 0.28 51.1 11.2 1.5 2.9 $40,905,618 6.3% $1,101,253 3.3% $30,855,296 $72,862,167 Lincoln 16 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Mason 21 0.40 69.3 16.1 2.1 4.0 $55,985,693 16.4% $1,034,153 5.8% $29,634,616 $86,654,463 Okanogan 28 0.08 0.0 0.0 0.0 0.0 $103,614 0.0% $4,928 0.0% $0 $108,542 Pacific 17 0.40 51.4 14.0 2.1 4.2 $33,069,521 16.6% $833,354 8.0% $23,162,805 $57,065,680 Pend Oreille 11 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pierce 270 0.28 369.4 66.6 6.9 13.5 $353,847,327 6.7% $6,886,930 2.5% $278,927,040 $639,661,298 San Juan 14 0.20 3.5 0.5 0.0 0.1 $4,421,531 3.6% $105,581 1.7% $4,044,303 $8,571,415 Skagit 48 0.20 70.7 13.9 1.6 3.1 $59,313,008 7.0% $951,686 2.1% $35,713,338 $95,978,032 Skamania 10 0.12 0.6 0.1 0.0 0.0 $934,498 0.7% $28,995 0.4% $753,193 $1,716,686 Snohomish 223 0.20 287.1 51.3 5.3 10.4 $274,105,772 6.2% $5,009,383 2.2% $218,486,045 $497,601,199 Spokane 154 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Stevens 44 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Thurston 78 0.32 198.3 41.5 4.9 9.5 $167,142,571 11.2% $3,065,911 3.9% $81,142,138 $251,350,620 Wahkiakum 2 0.32 4.3 1.2 0.2 0.3 $3,232,004 14.0% $81,403 6.8% $1,203,149 $4,516,556 Walla Walla 28 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whatcom 72 0.16 27.3 3.7 0.3 0.6 $32,730,916 2.6% $736,075 1.1% $33,482,728 $66,949,718 Whitman 26 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Yakima 104 0.08 3.5 0.3 0.0 0.0 $5,599,184 0.3% $169,362 0.2% $125,024 $5,893,570 Totals 2,426 0.44 2,543 507 60 117 $2,275,193,858 5.0% $45,300,454 1.9% $1,767,967,467 $4,088,461,779
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Figure 7.12 Cascadia Subduction Zone Interface M9.0 Scenario
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The previous damage and loss estimates are for specific scenario earthquake events. A complementary approach to evaluating the level of earthquake risk is “expected average annual losses”, that is, a probability-weighted calculation, taking into account the full range of possible damaging earthquake ground motions. Expected average annual losses for K–12 facilities are shown in Table 7.9 by county including the statewide totals. These results were calculated using HAZUS.
Table 7.9 Expected Average Annual Earthquake Losses
Business Minor Major Critical Building Loss Contents Loss Total Loss County # Schools Deaths Interuption Injuries Injuries Injuries ($) ($) ($) Loss ($) Adams 12 0.0 0.0 0.0 0.0 $12,631 $384 $10,478 $23,492 Asotin 12 0.0 0.0 0.0 0.0 $7,156 $225 $7,480 $14,860 Benton 60 0.1 0.0 0.0 0.0 $105,235 $3,168 $88,968 $197,370 Chelan 38 0.1 0.0 0.0 0.0 $136,415 $3,128 $91,208 $230,752 Clallam 35 1.0 0.2 0.0 0.1 $691,267 $13,140 $514,510 $1,218,917 Clark 130 1.5 0.3 0.0 0.1 $1,211,848 $34,139 $866,238 $2,112,225 Columbia 4 0.0 0.0 0.0 0.0 $2,758 $89 $2,279 $5,126 Cowlitz 46 0.5 0.1 0.0 0.0 $435,789 $12,086 $467,690 $915,565 Douglas 20 0.0 0.0 0.0 0.0 $41,908 $1,258 $39,547 $82,714 Ferry 13 0.0 0.0 0.0 0.0 $6,645 $205 $6,048 $12,898 Franklin 28 0.0 0.0 0.0 0.0 $42,337 $1,265 $33,129 $76,730 Garfield 2 0.0 0.0 0.0 0.0 $1,571 $50 $1,622 $3,242 Grant 54 0.1 0.0 0.0 0.0 $72,987 $2,199 $72,037 $147,224 Grays Harbor 44 0.8 0.2 0.0 0.1 $571,675 $15,527 $535,306 $1,122,508 Island 23 0.7 0.2 0.0 0.0 $557,452 $10,459 $362,117 $930,028 Jefferson 15 0.4 0.1 0.0 0.0 $278,668 $5,191 $172,548 $456,407 King 558 18.6 4.3 0.6 1.1 $14,270,981 $267,823 $9,154,474 $23,693,278 Kitsap 82 3.0 0.7 0.1 0.2 $2,234,366 $41,800 $1,763,236 $4,039,402 Kittitas 19 0.1 0.0 0.0 0.0 $89,965 $1,970 $67,747 $159,682 Klickitat 22 0.0 0.0 0.0 0.0 $45,755 $1,348 $46,451 $93,554 Lewis 43 0.5 0.1 0.0 0.0 $401,922 $11,283 $359,103 $772,308 Lincoln 16 0.0 0.0 0.0 0.0 $9,833 $306 $8,148 $18,287 Mason 21 0.7 0.2 0.0 0.0 $500,005 $9,303 $419,196 $928,504 Okanogan 28 0.1 0.0 0.0 0.0 $69,293 $1,663 $51,921 $122,876 Pacific 17 0.2 0.1 0.0 0.0 $136,140 $3,666 $140,216 $280,022 Pend Oreille 11 0.0 0.0 0.0 0.0 $7,613 $243 $5,724 $13,580 Pierce 270 8.6 2.0 0.2 0.5 $6,584,441 $122,895 $4,285,269 $10,992,605 San Juan 14 0.1 0.0 0.0 0.0 $122,470 $2,308 $103,054 $227,832 Skagit 48 1.0 0.2 0.0 0.1 $784,984 $14,817 $731,213 $1,531,014 Skamania 10 0.0 0.0 0.0 0.0 $38,393 $1,122 $29,556 $69,072 Snohomish 223 6.5 1.5 0.2 0.4 $4,989,298 $93,632 $3,363,581 $8,446,512 Spokane 154 0.1 0.0 0.0 0.0 $138,083 $4,408 $103,206 $245,697 Stevens 44 0.0 0.0 0.0 0.0 $25,397 $795 $25,834 $52,027 Thurston 78 2.6 0.6 0.1 0.1 $1,920,301 $35,697 $1,265,167 $3,221,165 Wahkiakum 2 0.0 0.0 0.0 0.0 $11,937 $328 $10,993 $23,257 Walla Walla 28 0.0 0.0 0.0 0.0 $35,861 $1,131 $24,373 $61,365 Whatcom 72 1.1 0.2 0.0 0.1 $940,960 $18,257 $748,163 $1,707,381 Whitman 26 0.0 0.0 0.0 0.0 $15,548 $490 $15,770 $31,809 Yakima 104 0.3 0.0 0.0 0.0 $309,709 $9,156 $292,182 $611,047 Totals 2,426 49 11 1 3 $37,859,596 $746,954 $26,285,782 $64,892,332
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The average annual casualty estimates above are shown with fractional deaths and injuries, to avoid rounding errors and to avoid showing zero casualties when a small number are expected statistically. These fractional casualties are interpreted probabilistically. For example, the average earthquake deaths in Pierce County schools are estimated to be 0.5 per year. This means an average of 50 deaths per 100 years. This means that 50 deaths could happen next week, next year, or ten years from now, or not for many decades into the future. However, a large earthquake could also cause significantly more than 50 deaths. The 0.5 deaths per years is simply a statistical estimate of the long-term average death rate.
7.8 Seismic Hazard and Risk Assessments at the Campus- and Building-Levels The previous sections of this chapter provided an overview of seismic hazards and seismic risk at the statewide level. In considering seismic risk at the campus- or building-level, it is important to note that the absence of previous earthquake damage does not mean that the level of earthquake risk is low. A campus with no history of earthquakes may still have a high seismic risk, because the return periods for major earthquakes are relatively long. More detailed campus or building-level seismic hazard and seismic risk assessments require more detailed data on a building-by-building basis. Statewide-level assessments provide a very useful initial screening, but are not accurate enough to guide mitigation decision making and priorities for a single campus or building. Detailed guidance for seismic hazard and risk assessments at the district, campus, or building- level is provided in the Mitigation Planning Toolkit. The campus-level and building-level seismic hazard and risk assessments have been incorporated into the ICOS Pre-Disaster Mitigation Database, including available GIS data layers and step-by-step guidance to facilitate entry of campus- and building-specific data. The process has been simplified and automated to the extent practicable and ICOS includes exportable report tables at both the campus-level and building-level. The synopsis below outlines the main steps.
Campus-Level Seismic Hazard and Risk Assessments: Main Steps
The ICOS Pre-Disaster Mitigation Database automates the campus-level seismic hazard analysis by auto-completing earthquake ground shaking data, site-class (soil/rock types), and liquefaction potential from USGS and DNR GIS data layers.
Recommendations and priorities for building-level risk assessments and geotechnical evaluation are based on the level or earthquake ground shaking hazard and on the liquefaction potential, respectively. Building-Level Seismic Hazard and Rick Assessments: Main Steps
The ICOS building-level assessments for earthquakes require additional data, including the building structural type and the building code (Uniform Building Code or International Building Code) and the code year for a building’s seismic design. If the building code and year are not known, the year built is used as a proxy for the building
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code and year, taking into account that Washington typically adopts building codes on July 1 of the year following the publication of a building code and that buildings permitted before code adoption may still be constructed after the adoption date for a new code.
The ICOS building-level assessment also requires identification of whether a building has significant vertical or horizontal irregularities, either of which increases a building’s seismic vulnerability.
From this data and the time-history of the seismic provisions in the Washington State building codes, quantitative estimates of a building’s seismic vulnerability is done automatically in ICOS by interpolations between seismic fragility curves from HAZUS.
Based on the above information, ICOS auto-generates recommendations and priorities for more detailed study of the buildings which most likely have significant seismic deficiencies and thus require more detailed evaluation.
The suggested approach for more detailed evaluation is based on the industry-standard American Society of Civil Engineers (ASCE) publication 41-13: Seismic Evaluation and Retrofit of Existing Buildings. Further details of the suggested approach are provided in the Technical Guidance Manual that is part of the Mitigation Planning Toolkit. ASCE 41- 13 is a combined updated version of two previous publications: ASCE 31-03 Seismic Evaluation of Existing Buildings and ASCE 41-06 Seismic Rehabilitation of Existing Buildings.
Prioritize seismic mitigation measures based on the results of the detailed seismic risk assessments for selected buildings. Prioritization can also consider the vulnerability, occupancy, and importance of each building, as well as benefit-cost analysis results.
Complete seismic retrofits for the highest priority buildings as funds become available. The Washington State Seismic Safety Committee, Washington Department of Natural Resources, and the Washington Military Department Emergency Management Division completed a pilot seismic risk assessment using the ASCE 31-03 method noted above (the precursor publication that has been replaced by ASCE 41-13).12 This pilot study for schools in the Aberdeen and Walla Walla School Districts is a good example of the use of the ASCE methodology to evaluate the level of seismic risk at the building level.
7.9 Earthquake Hazard Mitigation Measures for K–12 Facilities Typical Seismic Mitigation Measures There are several possible types of earthquake mitigation measures for K–12 facilities, including:
Replacement of seismically vulnerable buildings with buildings that meet the seismic provisions in the current building code.
Structural retrofits for buildings.
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Nonstructural retrofits for buildings and contents.
Installation of emergency generators for buildings with critical functions including designated emergency shelters.
Enhanced emergency planning, including earthquake drills. Replacement of seismically vulnerable buildings, with new buildings built to current seismic provisions in the building code, almost always results in better seismic performance than retrofitted buildings. It is rarely, if ever, possible to bring an older building up to 100 percent of the seismic performance of a current-code building. A new replacement building also has other advantages such as energy efficiency and meeting current functionality objectives. Of course, the major impediment to widespread replacement of seismically vulnerable buildings is the cost. Structural seismic retrofits of buildings involve strengthening the structural elements to resist horizontal and vertical forces on the building and keep a building from falling down including foundations, bearing walls, beams, columns, and floor and roof diaphragms. Doing structural seismic retrofits may be especially cost effective when done concurrently with building remodeling or modernization projects. Nonstructural seismic retrofits involve bracing or anchoring of nonstructural building components such as mechanical, electrical and plumbing systems, HVAC systems, and building contents. Typical targets for nonstructural mitigation are items where falling creates significant life safety risk, and/or items with high monetary values, or items that are important for facility operability. Installation of emergency generators may be appropriate for buildings with critical functions to help ensure post-earthquake operability. Such mitigation projects may be done in conjunction with seismic retrofits (for seismically vulnerable buildings) or without seismic retrofits (for buildings whose seismic performance is adequate). Enhanced emergency planning does not reduce damages and losses in future earthquakes but may reduce casualties via duck-and-cover drills and evacuation drills. Enhanced emergency planning may also reduce post-earthquake recovery time by being better prepared for earthquake events. FEMA mitigation grants, which typically provide 75 percent of total project costs, are potentially available for all of the above types of seismic mitigation measures except for building replacements. FEMA has funded retrofits of many seismically vulnerable buildings. Seismic Retrofit Costs for K–12 Facilities
Seismic retrofit costs for a given K–12 building vary tremendously depending on many factors, including:
The size and structure type of the building.
The extent and type of seismic deficiencies in the building.
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The level of seismic performance desired after retrofit.
Location within Washington, because location affects the level of seismic design and construction costs vary with location. Given the above factors, it is not possible to make a single estimate of “typical” seismic retrofit costs per school building. Seismic retrofit costs can range from about $5/SF (cripple wall bracing for a portable classroom) to well above $100/SF for a major structural retrofit of an unreinforced masonry building with major deficiencies. As a rough generalization, many seismic retrofits range from $50/SF to $100/SF or more. Total project costs are often much higher because in many cases seismic retrofits are done concurrently with other remodeling or upgrades of a building’s electrical, plumbing, and HVAC systems. Retrofitting every school building in Washington State that was designed and built to less than the current seismic code provisions is unrealistic from both the engineering perspective and the cost perspective. A very rough estimate of the total seismic retrofit costs for K–12 facilities in Washington State is that perhaps 10–20 percent of existing facilities might need to be retrofitted. The total inventory of K–12 facilities is approximately 165 million square feet. If we assume that average costs for seismic retrofits are in the range of $75 to $100 per square foot, then the total costs for seismic retrofits for 10–20 percent of the square footage range from about $1.2 billion to about $3.3 billion. For reference, British Columbia is undertaking a province-wide seismic retrofit program for schools with a total cost of approximately $3 billion. British Columbia has a population about 2/3 of Washington’s population. Scaling by the population, a similar statewide program in Washington might cost roughly $4 billion to $5 billion. Combining these estimates suggests that seismic retrofits for K–12 facilities in Washington might cost roughly $1 billion to $4 billion, depending on the scope of such an effort. This amounts to a cost of approximately $150 to $600 per person in Washington, or $7.50 to $30.00 per year, per person for a 20-year time period. However, seismic retrofit costs could be significantly lower than estimated above if, as seems likely, a significant fraction of the buildings with major seismic deficiencies are also functionally obsolete, in poor condition, or have major non-seismic deficiencies, and as a result they will be gradually replaced with new facilities in the future.
Seismic Retrofits for K–12 Facilities: Performance Objectives The range of possible seismic performance objectives are summarized in Table 7.10 on the following page. For schools, the most common seismic performance objective for retrofits is life safety. However, when resources are limited, implementing risk reduction measures, or collapse prevention, may significantly lower life safety risk, albeit without fully meeting the life safety criteria. When a building undergoes “substantial alteration” as defined in the IBC, the IEBC dictates the performance level based on the Occupancy Category of the building.
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For schools, retrofitting to immediate occupancy or post-earthquake operability, seismic performance level is not common. Retrofits to these levels might be appropriate for schools that are designated as emergency shelters or for K–12 facilities that are essential for district operability. In evaluating the desired seismic performance objective of a given building, it is essential to consider the level of ground shaking to which a retrofit meets the seismic performance level. For example, in ASCE 31-03, to meet a typical performance objective, the ground motions for the Life Safety and Collapse Prevention Objectives were the 10% in 50 year ground motion and the 2% in 50 year ground motion, respectively. However, under ASCE 41-13, these ground motions were reduced to the 20% in 50 year ground motion for the Life Safety Objective and the 5% in 50 year ground motion for the Collapse Performance Objective. For high occupancy, high importance buildings such as schools, the ground motions per ASCE 31-03 may be more appropriate design targets than those in ASCE 41-13, to the extent practicable for a given building.
Table 7.10 Possible Seismic Retrofit Performance Objectives
Seismic Performance Definition Objective
Incremental measures such as better connections between floors and walls in an unreinforced masonry building, bracing parapets or chimneys or limited Risk Reduction anchoring or bracing of building contents such as tall, heavy library shelves or non-structural building elements such as ceilings. Damage and life safety risk are reduced to some extent.
Structural retrofit to prevent collapse, although building may have major damage Collapse Prevention and may not be repairable.
Structural and nonstructural retrofit to provide life safety - collapse prevention Life Safety and unimpeded post-earthquake egress and access - although building may have major damage and not be repairable.
Structural and nonstructural retrofit to minimize damage so building is safe to Immediate Occupancy occupy post-earthquake. Building is repairable.
Structural and nonstructural retrofit to minimize damage so building is safe to Post-Earthquake Operability occupy post-earthquake and on-site backups to ensure continuity of critical utilities. Building is repairable.
Seismic retrofits are often completed at one time. However, in some circumstances, incremental seismic retrofits make sense. For example, a risk reduction measure to brace unreinforced masonry parapets above entrances to a building, and to brace a tall chimney, might be done right away, with a more comprehensive retrofit done later when funding becomes available.
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Incremental seismic retrofits may also be done during maintenance activities or during building modernization. In these cases, the marginal cost to add seismic retrofit measures to maintenance or modernization measures may be significantly lower than doing standalone seismic measures, because demolition and replacement of building elements is already included in the maintenance or modernization. Examples include: Adding plywood to strengthen a roof diaphragm and improving the roof to wall connections when roof covering is being replaced. Adding shear walls or improving floor to wall connections in a building undergoing major renovations.
Every K–12 facility in Washington State has some level of earthquake risk, even though the level of earthquake hazard varies markedly with location. Even in low seismic hazard areas of the state, there may be a few unusually vulnerable buildings with high enough risk to warrant more detailed evaluation. Therefore, all districts in Washington should include earthquakes in their mitigation plan.
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Chapter Eight: Tsunamis
8.1 Overview Tsunamis are ocean waves that are most commonly initiated by earthquakes with vertical deformation of the seafloor. Tsunami waves propagate outwards from the location of origin for very large distances. For example, a tsunami-triggering event anywhere in the Pacific Ocean will result in measurable tsunamis for the entire Pacific Ocean coastline. The mechanism by which undersea earthquakes trigger tsunamis is illustrated by the following figure.
Figure 8.1 Earthquake-Generated Tsunamis1
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In deep open ocean waters, tsunami waves have very long wavelengths, up to about 150 miles, and small amplitudes, ranging from a few inches to less than three feet. In the open ocean, tsunami waves may be barely perceptible to a ship. However, as tsunami waves reach shallow water near coastlines, the wavelengths shorten and their amplitudes increase markedly, reaching 10–20 feet or more. Once tsunami waves reach shore, the maximum run-up elevation and inundation distance inland vary markedly from event to event and location to location. Run-up elevations and inundation distances from the coast strongly depend not only on the offshore wave height but also on the near shore bathymetry and the detailed local topography at any given location. Tsunami inundations are flood events, but the level of damage may be much more severe than typical riverine or coastal flooding events for several reasons:
Tsunami inundation depths may be much higher than flood events.
Tsunami current velocities may be much higher than for flood events especially on outgoing surges as tsunami waters return to the ocean.
Tsunami inundations typically involve multiple episodes of flooding with both incoming and outgoing surges.
The depth, velocity, and multiple surges typically result in widespread damage to buildings, infrastructure, and vegetation that generate heavy debris loads that in turn further exacerbate tsunami damage. Multiple-surges experienced during tsunamis are illustrated in Figure 8.2.
Figure 8.2 Tsunami Surges in Hilo, Hawaii from M9.5 1960 Chile Earthquake2
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The power of tsunamis to result in nearly total destruction of buildings is illustrated by the photograph from the March 2011 Tohoku tsunami in Japan shown in Figure 8.3 below. The photograph shows the complete destruction of hundreds of buildings with little but the foundations remaining after the tsunami event. Only a few very robust buildings survived this tsunami.
Figure 8.3 Complete Destruction: March 2011 Tohoku Tsunami, Japan3
The March 2011 Tohoku tsunami in Japan was generated by a M9.0 earthquake on a subduction zone that is nearly identical to the Cascadia Subduction Zone along the coast of the Pacific Northwest. See Chapter Seven: Earthquakes for further information about earthquakes on the Cascadia Subduction Zone.
8.2 Tsunami Sources The most common source mechanism for tsunami generation is earthquakes within the ocean floor. Earthquake sources for tsunamis are commonly divided into two types:
Distant or far-field earthquake events within the Pacific Ocean that occur thousands of miles from Washington State. For far-field events, the warning time between an earthquake event that generates a tsunami, and arrival of tsunami waves, is several hours or more.
Local or near-field earthquake events that occur very close to the Washington coast. For near-field events, the warning time is generally an hour or less and may be as short as a few minutes. For Washington, the most important near-field earthquake sources are the
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Cascadia Subduction Zone and two faults crossing Puget Sound: the Seattle Fault Zone and the Tacoma Fault Zone. The following figure shows tsunami travel times for the 1964 Prince William Sound M9.2 earthquake that generated tsunamis throughout the Pacific Ocean. For Washington State, the travel times for this tsunami were between four and five hours.
Figure 8.4 Tsunami Travel Times: M9.2 1964 Prince William Sound Alaska Earthquake.4 (Travel Time Contours are Hours)
For Washington State, both distant and local earthquake sources contribute significantly to the total tsunami hazard. However, distant earthquakes generate much smaller tsunamis in Washington, with long warning times. Local earthquakes may generate much larger tsunamis with very short warning times. Local earthquake-generated tsunamis from earthquakes on the Cascadia Subduction Zone are the greatest tsunami hazard for coastal areas of Washington. The estimated return periods for major earthquake generated tsunamis are about 250 years to 500 years for Cascadia Subduction Zone earthquakes and about 1,000 years for a Seattle Fault Zone earthquake. The return period for the Tacoma Fault System is poorly known but may range from about 1,000 years to several thousand years.
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Tsunamis can also be generated by other sources including submarine landslides, landslides from land into bodies of water, and asteroid impacts. These non-earthquake sources can generate extremely large tsunamis but are much less likely to occur. These tsunami-generated sources have very long return periods, from thousands of years to hundreds of thousands of years to millions of years. Submarine landslides can cause significant tsunamis by displacing ocean water. They can generate significant tsunamis only if two conditions are both met 1) the volume of material moving in the landslide must be large, and 2) the landslide must move rapidly. Slow moving landslides don’t generate significant tsunamis. The return periods for major submarine landslides not generated by earthquakes are typically long because it takes thousands, or tens of thousands, of years for enough sediment to be deposited on an undersea slope to result in a substantial landslide. Submarine landslides generated by earthquakes are much more common. However, when earthquakes generate submarine landslides, it is typically the earthquake that generates the major tsunami, not the landslide. For completeness, we note that on-land landslides into the ocean can generate extreme tsunamis in very localized areas. The most dramatic example occurred in 1958 in Lituya Bay Alaska which is a narrow fjord about two miles wide and six miles long. An approximate 30 million cubic feet landslide created a wave about 800 feet high that denuded trees on the hillside across from the landslide to an elevation of about 1,600 feet. Run-up heights elsewhere in this bay ranged from about 30 feet to about 600 feet. There are no locations along the Washington Coast where such extreme localized landslide generated tsunamis can occur. However, locally damaging tsunamis can be generated by smaller landslides from steep slopes into the Pacific Ocean, Puget Sound, or other bodies of water in Washington. Asteroid impacts into the Pacific Ocean can generate large tsunamis, but these are extremely unlikely. Return periods for asteroid impacts of various sizes are not well determined, but all estimates yield very long return periods for large asteroid impacts. The estimated return period for impacts of one kilometer diameter asteroids is about 500,000 years.5, 6 The return period for an asteroid of this diameter hitting the Pacific Ocean would be about 1.5 million years. Reports in the popular press have sometimes suggested that tsunamis generated by asteroids could devastate the entire Pacific Ocean Coast. However, scientific analysis shows that ocean wide effects would require an asteroid diameter greater than two kilometers.7 The return period for asteroids of this diameter hitting the Pacific Ocean is likely greater than five million years. That is, such events have extremely low probabilities of occurring. Tsunamis can also be generated by nuclear explosions. Even very large nuclear explosions release far less energy than large asteroids (such as one kilometer diameter asteroid). Thus, while a nuclear explosion could result in a tsunami that might cause damage, it would not result in major Pacific-wide tsunamis.
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8.3 Historical Tsunamis Affecting Washington State
Local Tsunamis The written historical record of tsunamis in the Pacific Northwest extends for, at most, a few hundred years with more detailed records available for less than 200 years. However, paleoseismic studies have extended the record of tsunami events, and of earthquakes, that would have generated tsunamis to about the last 10,000 years. A great Cascadia Subduction Zone earthquake with an estimated magnitude of 9.0 occurred on January 26, 1700. The date and time of this earthquake was determined from detailed tsunami data from Japan. This earthquake generated a major tsunami that affected the entire Pacific Ocean Coastline. Subsequent geologic investigations in Washington have found that this earthquake caused much of the land on Washington’s outer cost to subside by about five feet, and there are numerous locations along the Pacific Coast, and the coast of Puget Sound, where tsunami-generated deposits have been identified on land. Based on analysis of these deposits, tsunami inundations occurred up to 30 feet above sea level at many coastal locations.
Paleoseismic studies by Goldfinger and Others8 have identified 41 previous major earthquakes on the Cascadia Subduction Zone with magnitudes estimated to range from about M8.0 to M9.0 over the past 10,000 years. This data suggests an average return period of about 250 years between major earthquakes. The average return period for a M9.0 mega-earthquake is estimated to be about 500 years; although, the intervals between major earthquakes vary substantially. It is believed that all of these Cascadia Subduction earthquakes would have generated substantial tsunamis affecting the Pacific and Puget Sound Coasts. There is also geologic evidence for an earthquake of about M7 on the Seattle Fault Zone about 1,100 years ago between the years 900 and 930. The uplift of the floor of Puget Sound generated a significant tsunami with inundation depths estimated to be up to 20 feet at the Seattle waterfront. Distant Tsunamis Most far-field tsunamis, generated by large earthquakes within the Pacific Ocean, have minor effects along the Washington Coast, with typical run-up heights ranging from a few inches to one or two feet. The most significant distant tsunami event occurred from the 1964 M9.2 Prince William Sound earthquake in Alaska. In this event, run-up heights of several feet were recorded at many locations along the Pacific Coast. Run-up heights between ten and 15 feet were recorded at a few locations including Ocean Shores, Moclips, Seaview, and Wreck Creek.9 Effect of Global Climate Change and Sea Level Rise Current consensus estimates of the expected rate of sea level rise over the next 50–100 years will result in significantly higher inundation depths for both tsunamis and floods. The projected
Page | 107 increase in inundation depths arises from a combination of sea level rise and expected beach erosion. A recent estimate for sea level rise over the next 100 years is 1.4 meters (about 4.6 feet), but a sea level rise up to 2.0 meters (about 6.5 feet) is possible.10 The inundation elevation for either tsunami or flood events would be increased by the amount of sea level rise. Thus, over the next 50 to 100 years the frequency of tsunami inundation, or coastal storm surge flooding, to a given elevation will increase significantly.
8.4 Tsunami Hazard Analysis and Mapping The major sources for tsunami hazards for the Washington Coast and the Puget Sound Coast are near-field earthquakes on the Cascadia Subduction Zone, the Seattle Fault Zone and the Tacoma Fault Zone. As noted previously, near-field earthquakes are capable of generating much larger tsunamis than far-field earthquakes. The Washington State Department of Natural Resources, in conjunction with other agencies, has prepared tsunami evacuation and inundation maps for many at-risk locations along the Washington Coast.
DNR has prepared tsunami evacuation maps for the following communities:11
Aberdeen – Hoquiam.
Amanda Park.
Bay Center.
Bellingham.
Clallam Bay.
Cosmopolis – South Aberdeen.
Hoh Reservation.
La Push.
Long Beach – Ilwaco.
Lummi Island.
Lummi Reservation.
Neah Bay.
North Cove – Tokeland – Shoalwater Bay Tribe.
Ocean Park - Ocean City – Copalis Beach – Pacific Beach – Moclips.
Ocean Shores.
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Point Roberts.
Port Angeles.
Port Townsend.
Queets.
Quinault.
Raymond – South Bend.
Sandy Point.
Sequim.
Taholah Ocean Tracts – Point Grenville.
Taholah Village.
Tsa’alal Village.
Westport – Grayland – Ocosta An important caveat on the existing tsunami maps is that not all locations on the coasts of the Pacific Ocean and Puget Sound have been mapped. Thus, some of the not-yet-mapped areas may have significant tsunami risk. Figure 8.5 on the following page shows coastal areas with and without tsunami mapping. An example tsunami evacuation map (Aberdeen–Hoquiam) is shown in Figure 8.6. Tsunami inundation maps showing the locations of K–12 facilities within or near mapped tsunami inundation zones are shown in Figures 8.7 to 8.19. The K–12 facilities shown in Figures 8.7 to 8.19 are listed in Tables 8.1, 8.2, and 8.3 which follow the figures.
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Figure 8.5 Tsunami Zones: Mapped and Unmapped
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Figure 8.6 Example Tsunami Evacuation Map/Brochure: Aberdeen – Hoquiam11
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Figure 8.6–Continued Example Tsunami Evacuation Map/Brochure: Aberdeen – Hoquiam11
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Figure 8.7 Tsunami Inundation Map: Overall
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Figure 8.8 Tsunami Inundation Map: Ferndale School District
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Figure 8.9 Tsunami Inundation Map: Burlington Edison School District
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Figure 8.10 Tsunami Inundation Map: La Conner School District
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Figure 8.11 Tsunami Inundation Map: Seattle School District
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Figure 8.12 Tsunami Inundation Map: North Beach School District
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Figure 8.13 Tsunami Inundation Map: Ocosta School District
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Figure 8.14 Tsunami Inundation Map: Ocean Beach School District
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Figure 8.15 Tsunami Inundation Map: Tacoma and Vicinity
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Figure 8.16 Tsunami Inundation Map: Cape Flattery School District
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Figure 8.17 Tsunami Inundation Map: Taholah School District
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Figure 8.18 Tsunami Inundation Map: Hoquiam – Aberdeen School Districts
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Figure 8.19 Tsunami Inundation Map: Raymond – South Bend School Districts
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8.5 Tsunami Hazard and Risk Assessment for K–12 Facilities As documented by the tsunami inundation maps shown on the previous pages, evaluation of the level of tsunami hazard has been completed for most, but not all, of the developed locations on the Washington coast. This evaluation included several steps:
Identify a range of earthquake events capable of generating significant tsunamis.
Model the tsunami generated by each event.
Model the deep water propagation of the tsunami wave from source to offshore of the site of interest.
Model the tsunami propagation in shallow water offshore from the site of interest.
Model the on-land run-up to determine the inundated area. The state-of-the-art of tsunami modeling has improved markedly in recent years. Nevertheless, there are substantial uncertainties in estimating the tsunami run-up elevation and inundation depth, at specific locations for a given tsunami-generating event, such as a M9.0 earthquake on the Cascadia Subduction Zone. The significant sources of uncertainty include:
Limited spatial resolution for near shore bathymetry and for onshore topography.
Limited accuracy for both the offshore and onshore elevation data.
Variability in sea level from tidal cycles and/or storm surge conditions.
Variability in the details of the fault rupture and vertical deformation of the seafloor for a given earthquake. For example, if there are ten M9.0 earthquakes on the Cascadia Subduction Zone over the next several thousand years, the tsunamis generated may vary substantially from event to event.
Tsunami wave reflection and refraction effects that may result in constructive or destructive interference between waves with significant increases or decreases in tsunami wave heights.
Possibility of larger than anticipated earthquakes on tsunami-generating faults or tsunamis generated on unknown faults. All of these factors combine to produce substantial uncertainties. The tsunami evacuation and inundation maps shown in the previous section are based on the “maximum considered” tsunami event for the tsunami modeling by DNR and other agencies, along with the best available data to estimate the tsunami run-up elevation and inundation depths for this event. At any given location, substantially higher tsunami run-up elevations and inundation depths (than those illustrated on the maps) are possible and may occur.
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For mitigation planning and evacuation planning, campuses with elevations less than 100 feet may have enough risk to warrant immediate evacuation to be implemented and the development of an evacuation plan for earthquakes that generate strong ground shaking at the campus. The above observations are based on the factors resulting in uncertainty in tsunami modeling and from experience in the March 2011 Tohoku, Japan earthquake. Many people who were outside the mapped tsunami inundation zones or who went to designated evacuation points died. The tsunami was much larger than anticipated, with inundation over a much wider area than anticipated, causing many designated evacuation locations to be inundated by the tsunami. For K–12 facilities, evaluation of the structural characteristics of buildings to determine the extent to which the building may be capable of withstanding tsunami forces is not necessary, unless a multi-story building is under consideration as a vertical evacuation shelter for tsunamis. For tsunamis, the predominant mitigation measure is immediate evacuation to safe elevations to minimize casualties. Detailed guidance for tsunami hazard and risk assessments at the campus-level is provided in the Mitigation Planning Toolkit. The campus-level tsunami hazard and risk assessments have been incorporated into the ICOS Pre-Disaster Mitigation Database, including available GIS data layers and step-by-step guidance to facilitate entry of campus-specific data. The process has been simplified and automated to the extent practicable and ICOS includes exportable report tables at the campus-level. The only circumstance when a building-level assessment would be made for tsunamis is if a multi-story building were being evaluated to determine whether it is robust enough to withstand both earthquake and tsunami forces, with a high level of confidence, so that the building could serve as a vertical evacuation structure during tsunamis if no natural high ground is reachable. The GIS data layers used for tsunami hazard and risk evaluation include the mapped tsunami zones, the distance to the coast, and the campus at-grade elevation. These data provide the basis for the initial tsunami risk categories shown in Table 8.1. For tsunamis, the predominant concern for K–12 facilities at risk is life safety. The ICOS Pre- Disaster Mitigation Database combines the parameters listed above with district-provided inputs, including the distance to the nearest safe haven for tsunamis and assessment of whether there are impediments along the evacuation route that could make evacuation problematic.
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Table 8.1 Tsunami Risk Categories
Number of Within Mapped Elevation Distance To Risk Category Campuses Tsunami Zone (Feet) Coast (Miles) High or Very High 38 YES All All Low or Moderate 68 NO Less than 30 Less than 5 Low 32 NO 30 to 50 Less than 5 Very Low 85 NO 50 to 100 Less than 5
Campuses at elevations above 100 feet have extremely low tsunami risk–essentially nil–except perhaps for extreme events much larger than anticipated tsunamis. Footnotes for the following tables:
The distance to the coast is an estimate from GIS data. Distances may differ.
The estimated campus elevations are based on GIS data (digital elevation maps) for the campus latitude and longitude in the OSPI database. Small errors in the latitude or longitude may result in substantial elevation errors, especially near the coast. For campus-specific tsunami risk assessments, surveyed elevation data for the campus are necessary.
Some campuses near the coast and at low elevations, but not within currently mapped tsunami zones, may have high or very high tsunami risk. The following tables identify 223 K–12 campuses at risk, or potentially at risk, from tsunami inundation in four groups as shown in Table 8.1.
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Table 8.2 Schools within Mapped Tsunami Inundation Zones
FACILITY INFORMATION TSUNAMI HAZARDS Within Distance Campus Elevation Mapped to Coast At Grade Facility Name District City Inundation (Straightline) (NAVD 1988) Zone? Milesa Feetb A.J. West Elementary School Aberdeen Aberdeen Yes 0.68 9.84 Alexander Young Elementary Aberdeen Aberdeen Yes 0.95 18.70 Birth to 3 Contracts Seattle Seattle Yes 0.49 17.06 Central Elementary School Hoquiam Hoquiam Yes 0.69 19.03 Chauncey Davis Elementary School South Bend South Bend Yes 2.10 17.39 Columbia Junior High School Fife Tacoma Yes 1.82 19.68 Developmental Preschool Raymond Raymond Yes 4.32 8.86 Edison Elementary School Burlington-Edison Edison Yes 0.06 1.97 Emerson Elementary School Hoquiam Hoquiam Yes 0.75 17.72 Fife High School Fife Tacoma Yes 1.38 15.75 Harbor High School Aberdeen Aberdeen Yes 0.53 11.15 Head Start Seattle Seattle Yes 0.49 17.06 Hopkins Preschool Center Aberdeen Aberdeen Yes 0.60 10.83 Hoquiam Homelink School Hoquiam Hoquiam Yes 0.45 9.84 Hoquiam Middle School Hoquiam Hoquiam Yes 0.59 19.03 Interagency Programs Seattle Seattle Yes 0.49 17.06 Learning Opportunity Center Fife Tacoma Yes 1.39 14.76 Long Beach Elementary School Ocean Beach Long Beach Yes 0.60 8.20 Miller Junior High School Aberdeen Aberdeen Yes 0.77 22.97 Neah Bay Elementary School Cape Flattery Neah Bay Yes 0.28 20.67 Neah Bay Junior Senior High School Cape Flattery Neah Bay Yes 0.27 20.67 North Beach Junior High School North Beach Ocean Shores Yes 0.36 20.01 North Beach Senior High School North Beach Ocean Shores Yes 0.38 20.01 North Bellingham Elementary Ferndale Ferndale Yes 3.14 9.84 Northwest Career & Technical Academy La Conner La Conner Yes 0.37 1.64 Ocean Beach Early Childhood Center Ocean Beach Long Beach Yes 0.60 8.86 Ocean Shores Elementary School North Beach Ocean Shores Yes 0.76 20.01 Ocosta Elementary School Ocosta Westport Yes 0.35 20.01 Ocosta Junior Senior High School Ocosta Westport Yes 0.49 20.01 Raymond Elementary School Raymond Raymond Yes 4.32 8.86 Raymond Home Link School Raymond Raymond Yes 4.32 8.86 Raymond Junior Senior High School Raymond Raymond Yes 4.32 8.86 South Bend High School South Bend South Bend Yes 2.07 16.73 Stevens Elementary School Aberdeen Aberdeen Yes 0.85 24.93 Taholah Elementary & Middle School Taholah Taholah Yes 0.40 18.04 Taholah High School Taholah Taholah Yes 0.39 18.37 Transportation Maintenance Center Hoquiam Hoquiam Yes 0.44 9.84 Washington Elementary School Hoquiam Hoquiam Yes 0.72 16.73
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Table 8.3 Schools within Five Miles of Coast and Elevation Below 30 Feet
FACILITY INFORMATION TSUNAMI HAZARDS Within Distance Campus Elevation Mapped to Coast At Grade Facility Name District City Inundation (Straightline) (NAVD 1988) Zone? Milesa Feetb 10th Street School Marysville Marysville No 1.15 25.59 Alki Elementary School Seattle Seattle No 0.20 16.08 Allen Elementary School Burlington-Edison Bow No 4.69 19.68 Barnes Elementary School Kelso Kelso No 4.12 20.01 Blue Heron Middle School Port Townsend Port Townsend No 0.72 27.56 Brinnon Elementary School Brinnon Brinnon No 0.21 22.64 Broadway Learning Center Longview Longview No 2.43 18.04 Cedar Program Coupeville Coupeville No 0.05 6.89 Central Elementary School Ferndale Ferndale No 3.80 26.57 Choice Alternative School Shelton Shelton No 0.62 29.20 Columbia Valley Garden Elem School Longview Longview No 2.26 12.80 Cosmopolis Elementary School Cosmopolis Cosmopolis No 2.02 27.56 Coweeman Middle School Kelso Kelso No 3.18 11.81 Decatur Elementary School Lopez Island Anacortes No 0.01 2.30 Harding School Longview Longview No 1.48 10.83 Heritage School Marysville Marysville No 1.23 27.23 Home Port Learning Center Bellingham Bellingham No 0.29 5.25 Hood Canal Elementary & Junior High Hood Canal Shelton No 0.95 25.59 Hoquiam High School Hoquiam Hoquiam No 0.62 23.29 Huntington Middle School Kelso Kelso No 3.78 20.01 J.M. Weatherwax High School Aberdeen Aberdeen No 0.57 20.01 Jenne-Wright Elementary School Central Kitsap Silverdale No 0.18 25.26 Kelso High School Kelso Kelso No 3.14 11.81 Kent Elementary School Kent Kent No 3.34 24.93 Kessler Elementary School Longview Longview No 1.47 10.50 La Conner Elementary School La Conner La Conner No 0.17 5.25 La Conner High School La Conner La Conner No 0.19 5.58 La Conner Middle School La Conner La Conner No 0.17 4.27 Lincoln Elementary School Hoquiam Hoquiam No 1.40 15.75 Longview LSD Administration Longview Longview No 2.76 19.03 Longview School District Special Longview Longview No 2.76 19.03 Services Loowit High School Kelso Kelso No 3.23 28.54 Mark Morris High School Longview Longview No 2.48 16.73 Marysville Arts and Technology High Marysville Marysville No 1.15 25.59 School
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Table 8.3–Continued Schools within Five Miles of Coast and Elevation Below 30 Feet
FACILITY INFORMATION TSUNAMI HAZARDS Within Distance Campus Elevation Mapped to Coast At Grade Facility Name District City Inundation (Straightline) (NAVD 1988) Zone? Milesa Feetb Marysville Coop Program Marysville Marysville No 1.30 27.56 McDermoth Elementary School Aberdeen Aberdeen No 0.56 22.31 Middle School Options North Kitsap Kingston No 0.47 26.90 Mint Valley Elementary School Longview Longview No 2.38 17.72 Monticello Middle School Longview Longview No 1.48 10.83 Mt. Solo Middle School Longview Longview No 0.81 26.57 Naselle-Grays River Naselle Elementary School Naselle No 2.32 13.78 Valley Naselle-Grays River Naselle Junior Senior High Schools Naselle No 2.31 14.11 Valley Neely O'Brien Elementary School Kent Kent No 3.24 24.93 Northlake Elementary School Longview Longview No 2.21 13.78 Ocean Park Elementary School Ocean Beach Ocean Park No 0.41 28.87 Off Campus Central Kitsap Silverdale No 0.19 28.87 Olympic Elementary School Longview Longview No 1.34 9.84 Out Of District Facility Renton Renton No 4.37 25.26 Pacific Beach Elementary School North Beach Pacific Beach No 0.24 26.90 Peninsula High School Peninsula Gig Harbor No 0.02 13.45 Queets-Clearwater Elementary School Queets-Clearwater Forks No 0.14 26.25 Quil Ceda Elementary School Marysville Marysville No 1.29 27.23 R. A. Long High School Longview Longview No 1.69 9.84 Rainier Beach High School Seattle Seattle No 1.72 28.87 Riverside Elementary School Puyallup Puyallup No 2.68 20.01 Robert Gray Elementary School Longview Longview No 2.32 19.03 Saint Helens Elementary School Longview Longview No 0.86 9.84 Saratoga School Stanwood-Camano Stanwood No 0.48 5.91 Stanwood Elementary School Stanwood-Camano Stanwood No 0.51 5.58 Stanwood Middle School Stanwood-Camano Stanwood No 0.78 7.87 Structured Learning Center Longview Longview No 1.20 9.84 Totem Middle School Marysville Marysville No 1.44 24.93 Twin Harbors - A Branch of New Market Aberdeen Aberdeen No 0.53 20.01 Skills Center Wallace Elementary School Kelso Kelso No 2.43 16.73 Woodland Administration Office Woodland Woodland No 2.05 26.90 Woodland High School Woodland Woodland No 2.35 27.89 Woodland Middle School Woodland Woodland No 2.14 29.86 Woodland Primary School Woodland Woodland No 1.98 21.00
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Table 8.4 Schools within Five Miles of Coast and Elevation Between 30 and 50 Feet
FACILITY INFORMATION TSUNAMI HAZARDS Within Distance Campus Elevation Mapped to Coast At Grade Facility Name District City Inundation (Straightline) (NAVD 1988) Zone? Milesa Feetb Aylen Junior High School Puyallup Puyallup No 4.92 33.46 Belfair Elementary School North Mason Belfair No 0.39 49.54 Catlin Elementary School Kelso Kelso No 3.25 31.50 Clallam Bay Elementary School Cape Flattery Clallam Bay No 0.27 41.01 Clallam Bay High and Elementary Cape Flattery Clallam Bay No 0.27 41.01 School Columbia Elementary School Washougal Washougal No 0.37 44.29 Conway School Conway Mount Vernon No 2.53 33.14 Custer Elementary Ferndale Custer No 4.85 36.42 Evergreen Elementary School Shelton Shelton No 0.68 35.43 Ferndale High School Ferndale Ferndale No 4.32 36.42 Fruit Valley Elementary School Vancouver Vancouver No 0.98 41.01 Karshner Elementary School Puyallup Puyallup No 4.68 35.43 Kent Elementary School - Old Kent Kent No 4.08 33.46 Kent Junior High School Kent Kent No 4.44 44.95 Liberty Elementary School Marysville Marysville No 1.80 36.42 Marysville Middle School Marysville Marysville No 1.95 44.29 Marysville Mountain View High School Marysville Marysville No 1.94 37.07 Marysville On-line Move Up Program Marysville Marysville No 2.03 39.37 Marysville Special Education School Marysville Marysville No 2.07 39.37 Mill Creek Middle School Kent Kent No 4.43 45.28 Renton Senior High School Renton Renton No 4.39 30.51 Richard Gordon Elementary School North Kitsap Kingston No 0.57 44.62 Robert Gray Elementary School Aberdeen Aberdeen No 0.93 40.03 Sartori Education Center Renton Renton No 4.74 36.09 School Home Partnership Program Marysville Marysville No 2.07 39.37 Skamania Elementary School Skamania Skamania No 0.21 41.99 South Lake High School Seattle Seattle No 1.55 41.01 South Shore K-8 School Seattle Seattle No 1.42 46.26 TEAM High School Woodland Woodland No 2.09 31.17 Transportation Maintenance Center Shelton Shelton No 0.62 30.84 Washougal Special Services Washougal Washougal No 1.12 46.92 Woodland Intermediate School Woodland Woodland No 3.61 31.82
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Table 8.5 Schools within Five Miles of Coast and Elevation Between 50 and 100 Feet
FACILITY INFORMATION TSUNAMI HAZARDS Within Distance Campus Elevation Mapped to Coast At Grade Facility Name District City Inundation (Straightline) (NAVD 1988) Zone? Milesa Feetb Adams Elementary School Seattle Seattle 0.53 90.22 Addams Middle School Seattle Seattle 3.93 71.52 Allen Creek Elementary School Marysville Marysville 2.24 55.12 Anacortes Middle School Anacortes Anacortes 0.49 74.15 Avanti High School Olympia Olympia 0.39 53.48 Bellingham High School Bellingham Bellingham 0.77 65.94 Birchwood Elementary School Bellingham Bellingham 0.85 79.40 Blaine Elementary School Blaine Blaine 0.49 61.68 Blaine High School Blaine Blaine 0.65 69.55 Blaine Middle School Blaine Blaine 0.60 64.96 Blaine Primary School Blaine Blaine 0.48 54.79 Bremerton High School Bremerton Bremerton 0.30 83.33 Brookside Elementary School Shoreline Lake Forest Park 4.18 64.30 Carrolls Elementary School Kelso Kelso 0.37 80.38 Cascade Elementary School Marysville Marysville 3.37 70.21 Cedarcrest School Marysville Marysville 3.37 60.04 Chimacum Creek Primary School Chimacum Port Hadlock 0.67 99.41 Clearview Alternative High School Ferndale Bellingham 3.58 87.27 Columbia Elementary School Bellingham Bellingham 0.41 67.91 Concord International School Seattle Seattle 0.55 63.65 Cooper Elementary School Seattle Seattle 0.61 96.46 Coupeville High School Coupeville Coupeville 0.99 94.49 Coupeville Middle School Coupeville Coupeville 0.96 90.55 Crossroads Community School Quilcene Quilcene 1.01 86.61 Dunlap Elementary School Seattle Seattle 1.30 57.09 Experimental Education Unit Seattle Seattle 3.29 70.54 Franklin High School Seattle Seattle 2.16 63.32 Friday Harbor High School San Juan Island Friday Harbor 0.13 96.46 Friday Harbor Middle School San Juan Island Friday Harbor 0.17 90.22 Garfield Elementary School Everett Everett 1.11 84.32 Gause Elementary School Washougal Washougal 1.14 98.75 Griffin Bay School San Juan Island Friday Harbor 0.32 92.85 Griffin Home Renton Renton 4.27 50.20 Grove Elementary School Marysville Marysville 2.81 53.81
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Table 8.5–Continued Schools within Five Miles of Coast and Elevation Between 50 Feet and 100 Feet
FACILITY INFORMATION TSUNAMI HAZARDS Within Distance Campus Elevation Mapped to Coast At Grade Facility Name District City Inundation (Straightline) (NAVD 1988) Zone? Milesa Feetb Hathaway Elementary School Washougal Washougal 0.58 69.88 Hawthorne Elementary School Seattle Seattle 2.56 97.44 Home Education Partnership Anacortes Anacortes 0.48 70.54 HomeConnection Oak Harbor Oak Harbor 0.73 60.37 Hough Elementary School Vancouver Vancouver 0.87 88.91 Hutch School Seattle Seattle 1.10 78.41 Ilwaco Middle High School Ocean Beach Ilwaco 0.33 53.81 Jane Addams K-8 School Seattle Seattle 3.93 77.10 Jemtegaard Middle School Washougal Washougal 1.14 68.90 John Muir Elementary School Seattle Seattle 2.32 70.21 Kellogg Marsh Elementary School Marysville Marysville 3.40 63.98 Kingston High School North Kitsap Kingston 0.56 79.72 Kingston Middle School North Kitsap Kingston 0.80 64.96 Madison Elementary School Olympia Olympia 0.46 68.57 Marshall Elementary School Marysville Marysville 4.11 69.88 Marysville Pilchuck High School Marysville Marysville 4.17 74.47 McGilvra Elementary School Seattle Seattle 3.27 94.49 Minter Creek Elementary School Peninsula Gig Harbor 0.28 56.43 Mountain View Elementary Ferndale Ferndale 4.27 87.60 Mountain View Elementary Port Townsend Port Townsend 0.41 88.25 MP Pathways of Choice Marysville Marysville 3.90 74.15 Naselle Youth Camp School Naselle-Grays River Naselle 0.78 85.96 Nathan Hale High School Seattle Seattle 3.77 72.51 North Middle School Everett Everett 0.81 88.58 North Whidbey Middle School Oak Harbor Oak Harbor 0.71 87.93 Oak Harbor Aadministrative Service Oak Harbor Oak Harbor 0.75 63.32 Center Oak Harbor Middle School Oak Harbor Oak Harbor 0.70 56.10 OASIS School K-12 Orcas Island Eastsound 0.32 82.68 Options High School Bellingham Bellingham 0.94 68.90 Orcas Island Elementary School Orcas Island Eastsound 0.31 85.63 Orcas Island High School Orcas Island Eastsound 0.33 96.46 Orcas Island Middle School Orcas Island Eastsound 0.29 80.38 Parents As Partners Port Angeles Port Angeles 0.35 84.64 Pass Program Everett Everett 0.98 76.77
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Table 8.5–Continued Schools within Five Miles of Coast and Elevation Between 50 Feet and 100 Feet
FACILITY INFORMATION TSUNAMI HAZARDS Within Distance Campus Elevation Mapped to Coast At Grade Facility Name District City Inundation (Straightline) (NAVD 1988) Zone? Milesa Feetb Pinewood Elementary School Marysville Marysville 2.66 55.12 Quilcene High And Elementary School Quilcene Quilcene 1.10 78.41 Saltars Point Elementary School Steilacoom Steilacoom 0.26 71.52 Science and Math Institute Tacoma Wa 0.20 91.86 Shuksan Middle School Bellingham Bellingham 1.21 94.16 Special Education Oak Harbor Oak Harbor 0.73 60.37 Special Education Port Angeles Port Angeles 0.35 84.64 Stuart Island Elementary School San Juan Island Friday Harbor 0.26 90.88 Tacoma School of the Arts Tacoma Tacoma 0.16 55.77 Tulalip Elementary School Marysville Marysville 0.21 85.30 Twin City Elementary School Stanwood-Camano Stanwood 2.10 97.11 Union Ridge Elementary School Ridgefield Ridgefield 2.11 97.77 Vaughn Elementary School Peninsula Vaughn 0.25 60.69 Waldron Island School Orcas Island Waldron Island 0.02 69.55 Whatcom Middle School Bellingham Bellingham 0.58 71.85 Whitney Elementary School Anacortes Anacortes 0.35 50.52 8.6 Tsunami Loss Estimates The magnitude of damages and casualties from any given tsunami event depends on several factors including:
The severity of the tsunami as measured by the run-up height, inundation depths, flow velocities, debris loads, and number of cycles of incoming and outgoing surges.
The number and size of inundated K–12 facilities.
The capacity of inundated facilities to withstand tsunami forces.
The occupancy of the inundated facilities at the time the tsunami occurs.
The effectiveness of evacuations to safe havens. This depends on how quickly evacuation starts and the distance/time to safe havens at high enough elevation to be outside the tsunami inundation area. Casualty estimates (the numbers of deaths and injuries) for K–12 facilities depend very strongly on the time of year, day of week, and time of day; because the occupancy of K–12 facilities varies markedly as a function of these variables. Typically, high occupancies only occur for seven or eight hours per day for about 180 days per year. Occupancies are generally lower for the “shoulder” hours outside of the normal school day for before and after school activities or special events. Over the course of an entire year–24 hours per day for 365 days–most K–12 facilities have significant occupancies for only about 15 percent to 20 percent of the time.
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That is, for 80–85 percent of the time, the occupancy for K–12 facilities will be very low or zero when a tsunami occurs. For completeness, there is also a very small probability that a tsunami will occur at a time of unusually high occupancy such as for a major sporting or other special event. The probability of this occurring is very low since such unusually high occupancies probably occur for less than one percent of the time in any given year. For earthquake-generated tsunamis, total casualties will depend on a facility’s earthquake performance as well as on the extent of tsunami inundation and the effectiveness of evacuations. Casualties may result from earthquake damage and earthquake damage may also impede and delay evacuations and thus result in higher numbers of casualties from the ensuing tsunami. Given these many variables, it is not possible to make precise estimates of the extent of damages and casualties for any given tsunami event. The estimates below should be interpreted as illustrating the approximate range of possible damages and casualties. For any given tsunami, damages and casualties may be lower or higher than these estimates, and the number of inundated campuses may be lower or higher than these estimates. We consider three possible tsunami scenarios:
A major distant tsunami event such as an M9.0 or larger earthquake in Alaska.
A major local tsunami event such as an approximately M7.0 earthquake on the Seattle Fault Zone or the Tacoma Fault Zone within Puget Sound.
A major local tsunami event from a great M9.0 or larger earthquake on the Cascadia Subduction Zone.
Distant Tsunami Events As previously discussed, most distant tsunami events result in coastal run-up heights of less than two feet. In this case, damages and casualties for K–12 facilities would almost certainly be nil. However, as illustrated by the 1964 M9.2 Prince William Sound Alaska earthquake event, some very large distant earthquakes can result in run-up heights of up to 10–15 feet at a few locations on the Washington Coast. Thus, in such events, a few campuses at elevations below about 15 feet might suffer damage. The dollar amount of damages to buildings and contents could range from nil to several million dollars if one or several campuses suffered moderate damage. Tens of millions of dollars of damages could occur if several campuses suffered major damage. Most likely, damages would be towards the low end of this range. The warning time for tsunami arrivals on the Washington Coast for distant tsunami events is at least four to five hours for Alaska earthquakes and approximately ten hours for earthquake in the western Pacific or southern Pacific. Thus, there is ample time for complete evacuation, and the casualties at K–12 facilities should be nil providing everyone heeds warnings and moves to high ground. In the worst case, with some people not evacuating, there could be a small number of deaths–most likely less than five.
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Local Tsunami Events: Puget Sound Earthquakes The tsunami inundation maps, and the tables listing schools with known or potential tsunami risk, show that there are about ten campuses in the Puget Sound area that are at risk. Major earthquakes on the Seattle Fault Zone or the Tacoma Fault Zone would likely result in major damage to many of these campuses. Furthermore, because of the uncertainties in predicting the exact inundation areas for any given tsunami event, it is possible that some campuses at low elevations outside of the mapped tsunami inundation areas may also suffer damage. There is an important caveat about Puget Sound earthquakes and tsunamis. Deep earthquakes, such as the 1949, 1965 and 2001 events in the Puget Sound area do not generate tsunamis (other than perhaps local tsunamis generated by landslides into bodies of water), because these earthquakes do not result in vertical deformation of the floor of Puget Sound. However, other types of earthquakes in the Puget Sound area can generate substantial tsunamis. Estimated tsunami damages to buildings and contents for K–12 facilities from major earthquakes on the Seattle or Tacoma Fault Zones might range from $10–$20 million at the low end to perhaps $100 million or more at the high end, depending on the number of campuses inundated. These estimates are based on the average building replacement values per square foot, average building sizes for elementary school, middle school, and high school campuses, and average contents replacement values. Many facilities suffering tsunami inundation will be a complete loss because the damage is complete or so severe that complete rebuilding is necessary or because the damage is severe enough that the community decides to build a new facility. Ideally, the new facility should be built out of the tsunami inundation zone, rather than to repair the existing damaged facility after a tsunami. Total damages to K–12 facilities in these events, including earthquake damages would be much higher. See Chapter Seven Earthquakes for earthquake loss estimates. The warning time for these very nearby events will be short everywhere in Puget Sound and very short, less than five minutes, for some locations near the fault. If a facility is occupied when a tsunami occurs and given the short warning time, casualties are likely for campuses with significant inundation (water depths of several feet or more) unless evacuation is extremely effective. For tsunamis generated by local earthquakes in Puget Sound, the number of casualties could range from none (if the tsunami occurs when the campuses are not occupied) to several hundred or perhaps 1,000 or more. Ten campuses inundated without evacuations before tsunami arrivals is a worst case scenario. For a given event, the number of casualties depends on the number of campuses inundated, on the inundation depths, and on the extent to which the campus is evacuated before inundation occurs. For events such as major earthquakes on the Seattle or Tacoma Fault Zones, with very short warning times, casualties are likely for any campuses within the inundation zone that are not evacuated when the tsunami arrives. M9.0 Earthquakes on the Cascadia Subduction Zone Local tsunami events from great M9.0 (or possibly higher) earthquakes on the Cascadia Subduction Zone will generate tsunamis affecting the entire Pacific Coast of Washington as well
Page | 137 as affecting rivers near the coast and Puget Sound. As shown in Tables 8.2, 8.3, and 8.4 there are 223 campuses at known or potential risk from these tsunami events. The warning time between the earthquake event that generates a tsunami and tsunami arrival at a given campus varies significantly with location, from approximately 15 minutes to about one hour. A M9.0 or greater earthquake will generate a major tsunami that will inundate all or nearly all of the 38 campuses within the mapped tsunami inundation zones and may well inundate others as well. For loss estimating purposes we assume inundation of about 38 campuses. With assumptions similar to those stated in the previous section, total damages in the range of $300– $500 million appear likely. For many campuses, the casualty rate may be lower than that estimated for the Puget Sound earthquake scenarios, because the warning time between the earthquake and tsunami arrival is somewhat longer. On the other hand, there are several campuses for which evacuation to safe havens may be nearly impossible since they are too far away from safe havens and cannot reach high ground before the arrival of tsunami waves. Furthermore, for M9.0 Cascadia Subduction Zone earthquakes, widespread coastal subsidence of several feet may result in flooding that blocks evacuation routes. Earthquake damage to bridges may block evacuation routes resulting in longer evacuation times. Evacuation routes may also be blocked by earthquake debris including downed power lines, fires, or hazmat releases. For tsunamis during normal school hours, the population at risk for the 38 campuses within the mapped tsunami zones is approximately 15,000 based on typical sizes (square feet) for elementary, middle, and high schools along with typical occupancies per 1,000 SF. For tsunamis during normal school hours, the number of casualties, deaths, and injuries for a scenario in which all 38 campuses are inundated will probably be very high. Under very optimistic conditions in this scenario, assuming that most occupants evacuate to safe havens before tsunami arrivals, perhaps from five to ten is estimated. More realistic estimates may be higher with perhaps 20–30 percent deaths. In the worst case scenario, with evacuations that are too slow, the casualty rate could possibly approach 50 percent, or as many as 7,500 deaths. In addition, there would be substantial numbers of injuries. Notwithstanding, it is important to recognize with the estimates above that it is not possible to make precise estimates of the extent of damages and casualties for any given tsunami event. The estimates above should be interpreted only as illustrating the approximate range of possible damages and casualties. For any given tsunami, the number of inundated campuses and the level of damages and casualties may be lower or higher than these estimates The above damage and loss estimates are summarized in the table below.
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Table 8.6 Tsunami Damage and Death Estimates for Tsunamis with Schools in Session
Number of Damage Estimates Death Estimates Tsunami Event Campuses Inundated Low Range High Range Low Range High Range
$1 million Distant Earthquake1 0 to 2 None None Less than 5 to $2 million
$10 million $100 million Puget Sound Earthquake2 2 to 10 50 to 100 500 to 1,000 to $20 million or higher $200 million to $400 million Cascadia M9.0 Earthquake 15 to 40+ 750 to 1,500 5,000 to 7,500 $150 million or higher
1Large magnitude earthquake in Alaska, Chile, Japan or elsewhere in the Pacific Ocean.
2Magnitude 7+ earthquake on the Seattle Fault, Tacoma Fault or Southern Whidbey Island Fault systems.
8.7 Tsunami Mitigation Measures
Evacuation Planning For tsunamis affecting K–12 facilities the highest priority is minimizing casualties. Therefore, for tsunamis, from M9.0 earthquakes on the Cascadia Subduction Zone or earthquakes on the Seattle or Tacoma Fault Zones, evacuation for facilities in or near mapped tsunami zones must begin immediately after any earthquake when strong ground shaking is experienced. Waiting until the earthquake source is identified and trying to determine whether or not a tsunami is likely may be a fatal mistake. For all K–12 facilities that are, or may be, at tsunami risk, the highest priority mitigation measure is robust emergency planning for evacuation before a tsunami arrives. Robust emergency planning means implementing the following steps:
Identify designated safe haven locations for tsunami evacuations. Designated safe haven locations should be at least 50 feet above sea level with a preference for higher elevations of 100 feet or more whenever possible.
For tsunami safe haven evacuation locations, the primary criterion should be the shortest possible travel time to reach a safe elevation. An ideal location would be at an elevation above 100 feet with available shelter for evacuees located at the shortest travel distance from the K–12 facility. It should be reachable by a route that does not include any bridge crossings or locations with other likely impediments to rapid pedestrian travel.
If an ideal location is not available, then the highest priority is immediate life safety. This means a short travel time to a safe location without shelter is preferable to longer travel time to a location with shelter. Evacuees can move to a longer term shelter, if necessary, after the full series of tsunami inundation waves has ceased.
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Identify the best (shortest travel time) evacuation routes, taking into account that coastal subsidence is likely to occur (for M9.0 Cascadia Subduction Zone events) and that bridges may not be passable because of earthquake damage.
To be effective during an actual tsunami event, evacuations must be practiced on a regular basis so that students and staff know exactly what to do when a tsunami is likely to occur including: o Begin evacuation immediately upon cessation of strong ground shaking, without taking time to gather possessions. o Proceed along designated routes to designated safe haven locations as quickly as possible. For distant tsunami-generating events, such as a major earthquake in Alaska, the warning time before tsunami arrivals is generally at least four or five hours. For such events, evacuation may still be required for low-elevation facilities, but the evacuation may occur over a longer time period than for local tsunami events. For distant events, evacuations can proceed by bus or automobile transport to locations that provide suitable temporary shelter. Vertical Evacuation Evacuation to natural high ground is the always the preferred evacuation choice for locations where natural high ground is high enough to be above the worst case tsunami and is reachable within the estimated arrival times. However, for existing K–12 facilities at locations where evacuation to natural high ground is impossible because of the travel time and distance before tsunami arrivals, the only evacuation possibility is vertical evacuation. Vertical evacuation means evacuation to structures near the K– 12 facility including:
Upper stories of multistory buildings if, and only if, the buildings have been thoroughly evaluated and determined to have adequate elevations to provide tsunami safety and adequate structural capacity to resist both earthquake damage and tsunami damage. Vertical evacuation to a structure that is at too low an elevation or is likely to have major damage or collapse from ground shaking or tsunami inundation provides little or no protection from tsunamis.
Engineered evacuation platforms that may be purpose-built for tsunami evacuation only or multi-purpose.
Engineered berms at high enough elevations that are designed to prevent failure from tsunami forces. Other Tsunami Mitigation Measures There are several other tsunami mitigation measures that may be effective in some circumstances, including:
Reinforcing a multi-story building to make it suitable for vertical evacuation.
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Abandoning a K–12 facility within a tsunami inundation zone and replacing it with a new facility well outside of the inundation zone.
Siting new facilities well outside the inundation zone whenever possible. If no such sites exist within a given community, design the new facility for vertical evacuation. Physical mitigation measures to minimize tsunami damage are perhaps possible in some circumstances but are probably rarely practical or cost-effective for K–12 facilities. Examples of physical mitigation measures include building berms or concrete barriers to protect a facility from tsunami inundation. This tsunami section of the Washington State K–12 Facilities Hazard Mitigation Plan provides a foundation of information and guidance to help school districts:
Determine whether any of their facilities have an unacceptably high level of risk for tsunamis.
Identify mitigation measures that will most effectively meet district priorities for reducing tsunami risk.
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Chapter Nine: Volcanic Hazards
9.1 Overview The Cascades, which run from British Columbia into northern California, contain more than a dozen major volcanoes and hundreds of smaller volcanic features. In the past 200 years, seven of the Cascade volcanoes in the United States have erupted including four in Washington: Mount St. Helens, Mount Baker, Glacier Peak, and Mount Rainier, as well Mount Hood in Oregon. Over the past 4,000 years (a geologically short time period), the most active volcano in the Cascades has been Mount St. Helens with about 14 eruptions.
Many other volcanoes in the Cascades are deemed active or potentially active. The Smithsonian Institution’s Global Volcanism Project1 lists seven active volcanoes in Washington. These volcanoes are listed below and include Mount Hood in Oregon which is close enough to potentially affect parts of Washington.
Table 9.1 Active Volcanoes in Washington1
Volcano Type Last Eruption Mount Baker Stratovolcano 1880 Glacier Peak Stratovolcano 1700 + 100 Mount Rainier Stratovolcano 1894 (?) Mount Adams Stratovolcano 950 AD (?) Mount St. Helens Stratovolcano 1980 - 2008 West Crater Volcanic Field 5750 BC (?) Indian Heaven Shield Volcanoes 6250 + 100 BC
Mount Hood (Oregon) Stratovolcano 1866
Numerous volcanoes of the Cascades differ markedly in their geological characteristics. The largest volcanoes are generally what geologists call composite or stratovolcanoes which have steep slopes because they are built mostly by flows of viscous lava. Shield volcanoes have gentle slopes because they are built mostly by flows of more fluid, low viscosity lavas. Volcanic fields are areas where volcanic activity occurs or large areas from numerous vents, fissures and cinder cones.
Photographs of the eight volcanoes listed in Table 9.1 are shown in Figure 9.1 on the following page.
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Figure 9.1 Washington Volcanoes and Mount Hood1
Mt. Rainier Mount St. Helens
Mt. Baker Glacier Peak
Mt. Adams West Crater Volcanic Field
Indian Heaven Shield Volcanoes Mt. Hood
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The current USGS ranking of threat potential for the eight volcanoes shown above is shown in the following table. Six of the eight volcanoes are ranked as having high to very high threat potential.
Table 9.2 USGS Volcano Threat Potential2
USGS Volcano Threat Potentiala Mount Baker High to Very High
Glacier Peak High to Very High
Mount Rainier High to Very High
Mount Adams High to Very High
Mount St. Helens High to Very High
West Crater Low to Very Low
Indian Heaven Low to Very Low
Mount Hood (Oregon) High to Very High
a Qualitative ranking based on rate of volcanic activity, explosiveness, and consequences.
Detailed information about specific volcanoes may be found on the following websites.
Table 9.3 Volcano Websites
Institution Website United States Geological Survey (USGS) www.usgs.gov USGS Cascades Volcano Observatory http://vulcan.wr.usgs.gov Smithsonian Institution (Global Volcanism Project) www.volcano.si.edu Washington State Department of Natural Resources www.dnr.wa.gov (see: Geology and Earth Resources Division)
9.2 Volcanic Hazard Types In Washington, awareness of the potential for volcanic eruptions was greatly increased by the 1980 eruption of Mount St. Helens that killed 57 people. In this eruption lateral blast effects covered 230 square miles and reached 17 miles northwest of the crater. Pyroclastic flows covered six square miles reaching five miles north of the crater, and landslides covered 23 square miles. Ash accumulations measured about ten inches at ten miles downwind, one inch at 60 miles downwind, and 0.5 inch at
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300 miles downwind. Lahars (mudflows) affected the North and South Forks of the Toutle River and ultimately reached the Cowlitz and Columbia Rivers as far as 70 miles from the volcano.
Volcanic eruptions often involve several distinct types of hazards to people and property, as evidenced by the Mount St. Helens eruption. Major volcanic hazards include lava flows, blast effects, pyroclastic flows, landslides or debris flows, ash falls, and lahars.
Proximal Volcanic Hazards (Effects near Volcanic Source Only) Lava flows are eruptions of molten rock. Lava flows for the major Cascades volcanoes tend to be thick and viscous forming cones and thus typically affect only areas very near the eruption vent. However, flows from the smaller mafic volcanoes may be less viscous flows that spread out over wider areas. Lava flows usually destroy everything in their path.
Blast effects may occur with violent eruptions, such as Mount St. Helens in 1980. Most volcanic blasts are largely upwards. However, the Mount St. Helens blast was lateral with impacts 17 miles from the volcano. Similar or larger blast zones are possible in future eruptions of any of the major Cascades volcanoes. Mount St. Helens and Glacier Peak have a history of explosive eruptions and lateral blasts which are a significant threat. Mount Rainier has had only limited explosive activity and one small blast in the past 10,000 years and thus has a low probability of future blasts. Mount Baker has had little explosive activity and has a low probability of future blasts. Mount Adams and Mount Hood are the least explosive volcanoes and have very low probabilities of future lateral blasts.
Pyroclastic flows are high-speed avalanches of hot ash, rock fragments and gases. Pyroclastic flows can be as hot as 1500o F and move downslope at 100 to 150 miles per hour. Pyroclastic flows are extremely deadly for anyone caught in their path.
Landslides, debris avalanches and debris flows are the rapid downslope movement of rocky material, snow and/or ice. Volcano landslides can range from small movements of loose debris to massive collapses of the entire summit or sides of a volcano. Landslides on volcanic slopes may be triggered by eruptions, earthquakes, or simply heavy rainfall.
Distal Volcanic Hazards (Effects at Considerable Distances from Volcanic Source) Lahars or mudflows are common during eruptions of volcanoes with heavy loading of ice and snow. These flows of mud, rock and water can rush down channels at 20 to 40 miles an hour and can extend for more than 50 miles. For some volcanoes, lahars are a major hazard because highly populated areas are built on lahar flows from previous eruptions.
Ash falls result when explosive eruptions blast rock fragments into the air. Such blasts may include tephra (solid and molten rock fragments). The largest rock fragments (sometimes called “bombs”) generally fall within two miles of the eruption vent. Smaller ash fragments (less than about 0.1”) typically rise thousands of feet into the air in eruption columns before falling back to earth. In very large eruptions, ash falls may total many feet in depth near the vent and extend for hundreds or even thousands of miles downwind.
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Volcanic Event Warning Times Most of the volcanic hazard events are related to eruptive activity. The United States Geological Survey (USGS) monitors active volcanoes, and most eruptive events would have precursory activity for days, weeks or months before a volcanic eruption. However, the exact time of an eruption cannot be predicted. It is also possible that some eruptions may have no precursory activity. For example, a major collapse of a volcanic peak could trigger a volcanic eruption. Some of these hazards including lahars, landslides, debris avalanches or debris flows may be triggered by non-volcanic events such as earthquakes or prolonged heavy rain,
Precursory activity, indicating a likely eruptive event in the near future that may affect one or more campuses, should put the school facilities and districts in high volcanic hazard locations on high alert. Possible actions range from diligent monitoring of USGS announcements, to practicing evacuation drills, to pro-active evacuations and school closures before an eruption occurs.
At present, there is a lahar warning system only for the Puyallup River and Carbon River valleys. For all schools within lahar hazard zones, immediate evacuation would be essential when an eruption begins. For schools in locations without the benefit of a lahar warning system, awareness if an approaching lahar would be limited to district officials being notified (which may or may occur in time) or from hearing the approaching lahar (which would provide at most five or ten minutes warning time). Therefore, for schools in lahar zones, the prudent action would be immediate evacuation as soon as an eruption starts, if proactive evacuation has not already occurred.
For schools within possible lateral blast zones, the warning time would be almost zero if a lateral blast occurs (a few minutes at most). This is not nearly enough time to evacuate. Lateral blasts are unlikely to occur; however, given the dire consequences, pro-active evacuation before an eruption occurs would be prudent if a volcanic eruption appears likely. Pro-active evacuation is extremely urgent if there are indications that a lateral blast may occur.
9.3 Volcanic Hazards for K–12 Facilities Most locations very near volcanic sources in Washington have little development and no K–12 facilities. However, there are some K–12 facilities located within the proximal volcanic hazard areas, as defined previously, including lateral blast zones for Mount Rainier and Glacier Peak lava flow and pyroclastic flow zones for Mount Adams. As discussed later in this chapter, the return periods for such events are very long ranging from 5,000 years or 10,000 years to 100,000 years or more. Therefore, the probability of such events is very low but not zero. However, there are many K–12 facilities at risk from the distal volcanic hazards: lahars and ash falls.
Lahars are most commonly initiated when volcanic activity rapidly melts snow and ice at high elevations on a volcano, when large volcanic landslides liquefy, or when lakes or reservoirs drain rapidly. Volcanic ash and debris constitutes part of the load carried by lahars, but as lahars flow downslope they pick up additional debris load from eroding sediments and vegetation. Large
Page | 146 lahars may be up to hundreds of yards wide and tens of yards deep and capable of carrying large boulders more than 30 feet in diameter.
Small lahars may flow only a short distance from the point of origin. However, larger lahars may flow very long distances. In 1980, lahars from Mount St. Helens reached the Columbia River near Longview, about 70 miles away. Lahars from Mount Rainier have reached Puget Sound and some communities downstream from Cascade volcanoes are built on historical lahar deposits.
Buildings inundated by lahar flows are generally totally destroyed and may be deeply buried under many feet of deposited debris.
Lahars pose an extreme life safety threat for K–12 facilities within the lahar inundation zone. When a lahar occurs, evacuation to safe locations well outside of the anticipated lahar inundation zone must be completed before arrival of the lahar at a facility’s location.
As noted previously, Mount St. Helens has been by far the most active volcano in the Cascades over the past, 4,000 years. Fortunately, there are no K–12 facilities within the mapped lahar zones for Mount St. Helens. However, there are K–12 facilities within the mapped lahar zones for the other volcanoes with lahar maps.
Volcanic Hazard Maps The figures on following pages show USGS mapped volcanic hazard zones for the six high, or very high, potentially threatening volcanoes listed in Table 9.2. They are Mount Adams (including the Indian Heaven shield volcanoes area), Mount Baker, Glacier Peak, Mount Hood, Mount Rainier and Mount St. Helens. Volcanic hazard zones have not been mapped for the West Crater Volcanic Field area.
The USGS lahar maps show volcanic events of several return periods. For example, for a given volcano, larger lahars have longer return periods–smaller annual probabilities–than smaller lahars. For details of each of the USGS volcanic hazard scenarios, see USGS publications for each volcano in the references for this chapter.
For mitigation planning purposes, the most important volcanic hazard information is:
Whether a given campus is within one or more USGS-mapped volcanic hazard zones.
If so, what are the return periods (annual probabilities) of volcanic events that may affect a given campus?
If a volcanic event occurs, can students and staff be evacuated to a safe area before the lahar or other volcanic phenomenon reaches the campus?
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Figure 9.2 Volcanic Hazard Map: Overall3, 4
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Figure 9.3 Mount Rainier Volcanic Hazards Map 4, 5
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Figure 9.3A Mount Rainier Volcanic Hazards Map: Northwest Area Close-Up4, 5
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Figure 9.3B Mount Rainier Volcanic Hazards Map: West Area Close-Up4, 5
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Figure 9.3C Mount Rainier Volcanic Hazards Map: Southwest Area Close-Up4, 5
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Figure 9.4 Mount Baker and Glacier Peak Lahar Map3, 6, 7
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Figure 9.4A Mount Baker and Glacier Peak Lateral Blast Zone Map3, 6, 7
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Figure 9.5 Mount Adams Volcanic Hazards Map3, 8
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Figure 9.6 Mount St. Helens Lahar Map3, 9
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Figure 9.7 Mount Hood Volcanic Hazards Map10, 11
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Ash Falls The USGS probabilistic ash fall maps are shown in Figure 9.8 on the following page. The maps show the probabilities of one centimeter (0.4 inch) or more of ash and ten centimeters (four inches) or more of ash over a 30-year time period.
The probabilistic ash fall contours are dominated by Mount St. Helens because this volcano is the most active volcano in the Cascades. The probabilistic ash fall contours are higher eastward from Mount St. Helens and the other volcanoes because the prevailing winds are from the west. Thus, significant ash falls are much more likely east of volcanoes than west.
For any volcanic eruption that generates ash, the thickness of ash accumulations decreases with distance from the volcano. Thus, locations nearest to Mount St. Helens, or to the other volcanoes, will receive the highest ash accumulations.
Depending on which volcano erupts and the volume of volcanic ash ejected by an eruption on prevailing winds, the thicknesses of ash fall will vary markedly with location. However, ash fall may affect a significant number of K–12 facilities in Washington.
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Figure 9.8 USGS Ash Fall Probabilistic Maps10
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In extreme ash fall events, ash accumulation depths may reach several feet or more. None of the volcanoes in the Cascades are believed capable of generating such extreme volumes of ash. However, most roofs cannot support more than a few inches of wet ash. Extreme ash thickness is not necessary for building roofs to collapse as a result of ash.
Most ash fall events impacting K–12 facilities are likely to be relatively minor with an inch or less of ash likely to occur. However, even minor amounts of ash fall can result in significant impacts.
The impacts of ash fall on K–12 facilities include health and several other disruptive effects including:
Moderately heavy ash falls may prevent some evacuations due to a combination of vehicular traffic disruption and health concerns that may preclude people being outside during heavy ash falls. In this case, shelter in place may be necessary, possibly for several days.
Respiratory problems for at-risk populations such as young children, people with respiratory problems, and the elderly.
Clogging of filters and possible severe damage to vehicle engines, furnaces, heat pumps, air conditioners, commercial and public building combined HVAC systems (heating, ventilation and air conditioning) and other engines and mechanical equipment.
Clean-up and ash removal from roofs, gutters, sidewalks, roads, vehicles, HVAC systems and ductwork, engines and mechanical equipment.
Impacts on public water supplies drawn from surface waters including degradation of water quality (high turbidity) and increased maintenance requirements at water treatment plants.
Possible electric power outages from ash-induced short circuits in distribution lines, transmission lines, and substations.
Disruptions of vehicular and air traffic.
9.4 Volcanic Hazards Risk Assessment There are 179 K–12 facilities located within USGS mapped volcanic hazard zones. The tabulated volcanic hazards include lahars, lava flows, pyroclastic flows and lateral blasts. The number of K–12 facilities within USGS mapped volcanic hazard zones is much smaller than the number of facilities subject to ash falls. However, the level of risk, especially life safety risk, is much higher from lahars, lava flows, pyroclastic flows and lateral blast events than from ash fall events. The USGS mapped volcanic hazard zones that include K-12 facilities are summarized in the table below.
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Table 9.4 USGS Mapped Volcanic Hazard Zones
USGS Mapped Return Period Probability Volcano Volcanic Hazard Type Hazard Zone (Years) in 50 Years
Adams Zone LA Lava Flows & Pyroclastic Deposits 30,000 0.17% Adams Zone LB Lava Flows & Pyroclastic Deposits 100,000 0.05% Adams Zone LC Lava Flows & Pyroclastic Deposits 1,000,000 0.005% Adams Zone DL Lahars 30,000 0.17% Baker Case 1 Lahars 1,000 4.88% Baker Case M Lahars 14,000 0.36% Baker Blast Zone Blast Zone 30,000 0.17% Glacier Peak GP Lahar1 Lahars 1,000 4.88% Glacier Peak GP Lahar2 Lahars 5,000 1.00% Glacier Peak & Baker Case M + Lahar Lahars 5,000 1.00% Hood Case DA Lahars/Flooding/Erosion 500 9.53% Rainier Case M Lahars 5,000 1.00% Rainier Case 1 Lahars 750 6.45% Rainier Case 2 Lahars 250 18.16% Rainier Blast Zone Blast Zone 20,000 0.25% 1 Lahars affecting areas near the volcano, such as Darrington. 2 Lahars affecting areas further from the volcano, near Puget Sound. The return periods above are mostly based on USGS estimates, supplemented with other estimates for hazard zones without USGS estimates. There are several important caveats regarding the interpretation of the estimated return periods shown above:
There is considerable uncertainty inherent in all of the return period estimates.
Within each hazard zone, there is a substantial range of possible sizes/severity of events. That is, volcanic events may be smaller or larger than the mapped zones.
Within each hazard zone, the return period for an event affecting a given location varies with location within the hazard zone. K–12 facilities that are closer to a volcano have a higher probability of being affected by an event because smaller events will reach locations nearer the volcano. Correspondingly, K–12 facilities that are further from a volcano have lower probabilities of being affected by an event.
K–12 facilities in close proximity to volcanoes may have significantly higher levels of volcanic hazard (shorter return periods) than those shown above in Table 9.4, because smaller events may affect these locations. These schools, include those in Concrete (Mt. Baker and Glacier Peak), Darrington (Glacier Peak), and the K–12 facilities very near Mt. Rainier.
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The following table provides a qualitative ranking of the level of volcanic hazards, based on the estimated return periods.
Table 9.5 Volcanic Hazard Levels
Return Period Volcanic Hazard Level (Years) 500 or less Very High 501 to 1,000 High 1,001 to 5,000 Moderate 5,001 to 10,000 Low 10,001 to 30,000 Very low more than 30,000 Extremely Low
Detailed guidance for volcanic hazard and risk assessments at the campus-level is provided in the Mitigation Planning Toolkit. The campus-level volcanic hazard and risk assessments have been incorporated into the ICOS Pre-Disaster Mitigation Database, including available GIS data layers and step-by-step guidance to facilitate entry of campus-specific data. The process has been simplified and automated to the extent practicable and ICOS includes exportable report tables at the campus-level. The GIS data layers used for volcanic hazard and risk evaluation include the mapped volcanic hazard zones for each volcano, the estimated return periods each of the volcanic events shown in in Table 9.4, the approximate distance between each campus and volcanoes that may affect a given campus, and the approximate travel time for lahars to reach a given campus. For volcanic hazards, the predominant concern for K–12 facilities at risk is life safety. The ICOS Pre-Disaster Mitigation Database combines the parameters listed above with district-provided inputs, including the distance to the nearest safe haven for lahars and assessment of whether there are impediments along the evacuation route that could make evacuation problematic. ICOS also auto-generates report tables summarizing the volcanic hazard and risk information for each campus at risk. The following tables identify the campuses located within mapped volcanic hazard zones and provide hazard and risk information for each campus.
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Table 9.6 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Rainer (Very High Hazard)
Approximate Volcanic Hazard Zones Distance Return Lahar Probability Volcanic Facility Name District City to Peak Lateral Governing Period Travel Time Case 1 Case 2 Case M (Miles) Blast Volcanic in 50 Years Hazard Level (Minutes) Lahar Lahar Lahar (Years) Zone Event Alpac Elementary School Auburn Pacific 36 87 Case 1 Case 2 Case M Case 2 250 18.16% Very High Aylen Junior High School Puyallup Puyallup 35 83 Case 1 Case 2 Case M Case 2 250 18.16% Very High Columbia Junior High School Fife Tacoma 38 91 Case 1 Case 2 Case M Case 2 250 18.16% Very High Daffodil Valley Elementary School Sumner Sumner 32 78 Case 1 Case 2 Case M Case 2 250 18.16% Very High E B Walker High School Puyallup Puyallup 34 82 Case 1 Case 2 Case M Case 2 250 18.16% Very High Eismann Elementary School Sumner Puyallup 30 73 Case 1 Case 2 Case M Case 2 250 18.16% Very High Fife High School Fife Tacoma 38 92 Case 1 Case 2 Case M Case 2 250 18.16% Very High Kalles Junior High School Puyallup Puyallup 34 80 Case 1 Case 2 Case M Case 2 250 18.16% Very High Karshner Elementary School Puyallup Puyallup 35 84 Case 1 Case 2 Case M Case 2 250 18.16% Very High Learning Opportunity Center Fife Tacoma 38 91 Case 1 Case 2 Case M Case 2 250 18.16% Very High Maple Lawn Elementary School Sumner Sumner 32 77 Case 1 Case 2 Case M Case 2 250 18.16% Very High Maplewood Elementary School Puyallup Puyallup 34 83 Case 1 Case 2 Case M Case 2 250 18.16% Very High McAlder Elementary School Sumner
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Table 9.7 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Rainer (High Hazard)
Approximate Volcanic Hazard Zones Distance Return Lahar Probability Volcanic Facility Name District City to Peak Lateral Governing Period Travel Time Case 1 Case 2 Case M (Miles) Blast Volcanic in 50 Years Hazard Level (Minutes) Lahar Lahar Lahar (Years) Zone Event Auburn Riverside High School Auburn Auburn 35 85 Case 1 Case M Case 1 750 6.45% High Carbonado Historical School 19 Carbonado Carbonado 20 49 Case 1 Case M Case 1 750 6.45% High Columbia Crest Elementary School Eatonville Ashford 18 44 Case 1 Case M Case 1 750 6.45% High Gildo Rey Elementary School Auburn Auburn 36 86 Case 1 Case M Case 1 750 6.45% High Ilalko Elementary School Auburn Auburn 35 85 Case 1 Case M Case 1 750 6.45% High Mt Baker Middle School Auburn Auburn 36 86 Case 1 Case M Case 1 750 6.45% High Olympic Middle School Auburn Auburn 37 88 Case 1 Case M Case 1 750 6.45% High Pioneer Elementary School Auburn Auburn 36 87 Case 1 Case M Case 1 750 6.45% High White Pass Elementary School White Pass Randle 25 59 Case 1 Case M Case 1 750 6.45% High Wilkeson Elementary School White River Wilkeson 21 51 Case 1 Case M Case 1 750 6.45% High
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Table 9.8 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Rainer (Moderate Hazard)
Approximate Volcanic Hazard Zones Distance Return Lahar Probability Volcanic Facility Name District City to Peak Lateral Governing Period Travel Time Case 1 Case 2 Case M (Miles) Blast Volcanic in 50 Years Hazard Level (Minutes) Lahar Lahar Lahar (Years) Zone Event Apolo High School Winlock Winlock 60 144 Case M Case M 5,000 1.00% Moderate Auburn Senior High School Auburn Auburn 38 90 Case M Case M 5,000 1.00% Moderate Barnes Elementary School Kelso Kelso 74 177 Case M Case M 5,000 1.00% Moderate Bonney Lake High School Sumner Bonney Lake 28 67 Case M LBZ Case M 5,000 1.00% Moderate Butler Acres Elementary School Kelso Kelso 74 177 Case M Case M 5,000 1.00% Moderate Byron Kibler Elementary School Enumclaw Enumclaw 26 63 Case M LBZ Case M 5,000 1.00% Moderate Cascade Middle School Auburn Auburn 39 93 Case M Case M 5,000 1.00% Moderate Chinook Elementary School Auburn Auburn 35 85 Case M Case M 5,000 1.00% Moderate Collins Alternative Programs White River Buckley 24 58 Case M LBZ Case M 5,000 1.00% Moderate Concord International School Seattle Seattle 53 126 Case M Case M 5,000 1.00% Moderate Coweeman Middle School Kelso Kelso 74 177 Case M Case M 5,000 1.00% Moderate Dick Scobee Elementary School Auburn Auburn 38 91 Case M Case M 5,000 1.00% Moderate Elk Ridge Elementary School White River Buckley 24 58 Case M LBZ Case M 5,000 1.00% Moderate Enumclaw Office Enumclaw Enumclaw 25 60 Case M LBZ Case M 5,000 1.00% Moderate Enumclaw Middle School Enumclaw Enumclaw 25 60 Case M LBZ Case M 5,000 1.00% Moderate Enumclaw Senior High School Enumclaw Enumclaw 25 60 Case M LBZ Case M 5,000 1.00% Moderate Foothills Elementary School White River Buckley 26 64 Case M LBZ Case M 5,000 1.00% Moderate Fort Stevens Elementary School Yelm Yelm 40 96 Case M Case M 5,000 1.00% Moderate Glacier Middle School White River Buckley 24 58 Case M LBZ Case M 5,000 1.00% Moderate Huntington Middle School Kelso Kelso 74 178 Case M Case M 5,000 1.00% Moderate Kelso KSD Administration Building Kelso Kelso 74 178 Case M Case M 5,000 1.00% Moderate Kelso High School Kelso Kelso 74 178 Case M Case M 5,000 1.00% Moderate Kelso Virtual Academy Kelso Kelso 74 178 Case M Case M 5,000 1.00% Moderate Kent Elementary School Kent Kent 42 102 Case M Case M 5,000 1.00% Moderate Kent Elementary School - Old Kent Kent 42 101 Case M Case M 5,000 1.00% Moderate Kent Junior High School Kent Kent 42 101 Case M Case M 5,000 1.00% Moderate Lakeland Hills Elementary School Auburn Auburn 34 83 Case M Case M 5,000 1.00% Moderate Liberty Ridge Elementary School Sumner Sumner 27 64 Case M LBZ Case M 5,000 1.00% Moderate Loowit High School Kelso Kelso 74 177 Case M Case M 5,000 1.00% Moderate McKenna Elementary School Yelm McKenna 38 92 Case M Case M 5,000 1.00% Moderate Mill Creek Middle School Kent Kent 42 101 Case M Case M 5,000 1.00% Moderate Mill Pond Elementary School Yelm Yelm 41 98 Case M Case M 5,000 1.00% Moderate Mountain Meadow Elementary School White River Buckley 24 58 Case M LBZ Case M 5,000 1.00% Moderate
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Table 9.9 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Rainer (Moderate Hazard)
Approximate Volcanic Hazard Zones Distance Return Lahar Probability Volcanic Facility Name District City to Peak Lateral Governing Period Travel Time Case 1 Case 2 Case M (Miles) Blast Volcanic in 50 Years Hazard Level (Minutes) Lahar Lahar Lahar (Years) Zone Event Mountain View Middle School Sumner Bonney Lake 28 67 Case M LBZ Case M 5,000 1.00% Moderate Neely O'Brien Elementary School Kent Kent 43 104 Case M Case M 5,000 1.00% Moderate Out Of District Facility Renton Renton 47 113 Case M Case M 5,000 1.00% Moderate Ridgeline Middle School Yelm Yelm 41 99 Case M Case M 5,000 1.00% Moderate Showalter Middle School Tukwila Seattle 49 116 Case M Case M 5,000 1.00% Moderate Southwood Elementary School Enumclaw Enumclaw 25 60 Case M LBZ Case M 5,000 1.00% Moderate Southworth Elementary School Yelm Yelm 43 102 Case M Case M 5,000 1.00% Moderate Special Education Kelso Kelso 74 178 Case M Case M 5,000 1.00% Moderate Special Education School Auburn Auburn 38 91 Case M Case M 5,000 1.00% Moderate Special Education School Enumclaw Enumclaw 25 60 Case M LBZ Case M 5,000 1.00% Moderate Sunrise Elementary School Enumclaw Enumclaw 25 60 Case M LBZ Case M 5,000 1.00% Moderate Terminal Park Elementary School Auburn Auburn 37 89 Case M Case M 5,000 1.00% Moderate Thunder Mountain Middle School Enumclaw Enumclaw 27 65 Case M LBZ Case M 5,000 1.00% Moderate Toledo Alternative Options Toledo Toledo 60 144 Case M Case M 5,000 1.00% Moderate Toledo Elementary School Toledo Toledo 60 145 Case M Case M 5,000 1.00% Moderate Toledo High School Toledo Toledo 60 143 Case M Case M 5,000 1.00% Moderate Toledo Middle School Toledo Toledo 60 144 Case M Case M 5,000 1.00% Moderate Tukwila Elementary School Tukwila Tukwila 48 115 Case M Case M 5,000 1.00% Moderate Victor Falls Elementary School Sumner Bonney Lake 28 68 Case M LBZ Case M 5,000 1.00% Moderate Washington Elementary School Auburn Auburn 38 90 Case M Case M 5,000 1.00% Moderate West Auburn Senior High School Auburn Auburn 38 91 Case M Case M 5,000 1.00% Moderate Westwood Elementary School Enumclaw Enumclaw 29 69 Case M Case M 5,000 1.00% Moderate White Pass Junior Senior High School White Pass Randle 25 60 Case M LBZ Case M 5,000 1.00% Moderate White River High School White River Buckley 24 58 Case M LBZ Case M 5,000 1.00% Moderate White River Special Education Services White River Buckley 24 57 Case M LBZ Case M 5,000 1.00% Moderate Winlock Middle School Winlock Winlock 60 144 Case M Case M 5,000 1.00% Moderate Winlock Senior High School Winlock Winlock 60 144 Case M Case M 5,000 1.00% Moderate Yelm Extension School Yelm Yelm 41 98 Case M Case M 5,000 1.00% Moderate Yelm High School Yelm Yelm 40 96 Case M Case M 5,000 1.00% Moderate Yelm Middle School Yelm Yelm 41 97 Case M Case M 5,000 1.00% Moderate Yelm Prairie Elementary School Yelm Yelm 40 96 Case M Case M 5,000 1.00% Moderate District Offices Toledo Toledo 60 144 Case M Case M 5,000 1.00% Moderate
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Table 9.10 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Rainer (Very Low Hazard)
Approximate Volcanic Hazard Zones Distance Return Lahar Probability Volcanic Facility Name District City to Peak Lateral Governing Period Travel Time Case 1 Case 2 Case M (Miles) Blast Volcanic in 50 Years Hazard Level (Minutes) Lahar Lahar Lahar (Years) Zone Event Eatonville Developmental Preschool Eatonville Eatonville 24 N/A LBZ LBZ 20,000 0.25% Very Low Eatonville Elementary School Eatonville Eatonville 24 N/A LBZ LBZ 20,000 0.25% Very Low Eatonville High School Eatonville Eatonville 24 N/A LBZ LBZ 20,000 0.25% Very Low Eatonville Middle School Eatonville Eatonville 24 N/A LBZ LBZ 20,000 0.25% Very Low Emerald Ridge High School Puyallup Puyallup 28 N/A LBZ LBZ 20,000 0.25% Very Low Frontier Junior High School Bethel Graham 28 N/A LBZ LBZ 20,000 0.25% Very Low Glacier View Junior High School Puyallup Puyallup 28 N/A LBZ LBZ 20,000 0.25% Very Low Kapowsin Elementary School Bethel Graham 28 N/A LBZ LBZ 20,000 0.25% Very Low Nelson Elementary School Bethel Graham 28 N/A LBZ LBZ 20,000 0.25% Very Low Weyerhaeuser Elementary School Eatonville Eatonville 28 N/A LBZ LBZ 20,000 0.25% Very Low
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Table 9.11 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Baker or Glacier Peak
Volcanic Hazard Zones Distance Distance Glacier to Approximate to Approximate Mount Baker Return Volcanic Lahar Lahar Peak Governing Probability Facility Name District City Mount Glacier Period Hazard Travel Time Travel Time Lateral Volcanic in 50 Years Baker Peak Case 1 Case M (Years) Level (Minutes) (Minutes) Blast GP Lahar Event (Miles) (Miles) Lahar Lahar Zone Central Elementary School Ferndale Ferndale 36 86 Case 1 Case M Case 1 1,000 4.88% High Educational Resource Center Mount Baker Deming 19 46 Case 1 Case M Case 1 1,000 4.88% High Mount Baker Senior High School Mount Baker Deming 19 46 Case 1 Case M Case 1 1,000 4.88% High Nooksack Valley Connections Nooksack Valley Everson 26 63 Case 1 Case M Case 1 1,000 4.88% High Nooksack Valley Middle School Nooksack Valley Everson 26 63 Case 1 Case M Case 1 1,000 4.88% High North Bellingham Elementary Ferndale Ferndale 37 89 Case 1 Case M Case 1 1,000 4.88% High Alternative Education at Nooksack ValleyNooksack Valley Everson 26 61 Case M Case M 14,000 0.36% Very Low Nooksack Elementary School Nooksack Valley Everson 25 60 Case M Case M 14,000 0.36% Very Low Nooksack Valley High School Nooksack Valley Everson 26 61 Case M Case M 14,000 0.36% Very Low Nooksack Valley Special Services Nooksack Valley Everson 26 61 Case M Case M 14,000 0.36% Very Low Sumas Elementary School Nooksack Valley Sumas 25 61 Case M Case M 14,000 0.36% Very Low Darrington Elementary School Darrington Darrington 25 59 GP Lahar1 GP Lahar1 1,000 4.88% High Darrington Middle School Darrington Darrington 25 59 GP Lahar1 GP Lahar1 1,000 4.88% High Darrington Senior High School Darrington Darrington 25 59 GP Lahar1 GP Lahar1 1,000 4.88% High Madison Elementary School Mount Vernon Mount Vernon 60 145 GP Lahar2 GP Lahar2 5,000 1.00% Moderate Saratoga School Stanwood-Camano Stanwood 59 142 GP Lahar2 GP Lahar2 5,000 1.00% Moderate Stanwood Elementary School Stanwood-Camano Stanwood 59 142 GP Lahar2 GP Lahar2 5,000 1.00% Moderate Stanwood Middle School Stanwood-Camano Stanwood 58 140 GP Lahar2 GP Lahar2 5,000 1.00% Moderate 1 Lahars affecting areas near the volcano, such as Darrington. 2 Lahars affecting areas further from the volcano, near Puget Sound.
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Table 9.12 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Baker and Glacier Peak
Volcanic Hazard Zones Distance Distance Glacier to Approximate to Approximate Mount Baker Return Volcanic Lahar Lahar Peak Governing Probability Facility Name District City Mount Glacier Period Hazard Travel Time Travel Time Lateral Volcanic in 50 Years Baker Peak Case 1 Case M (Years) Level (Minutes) (Minutes) Blast GP Lahar Event (Miles) (Miles) Lahar Lahar Zone Allen Elementary School Burlington-Edison Bow 32 64 154 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Burlington-Edison Alternative School Burlington-Edison Burlington 32 62 148 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Burlington-Edison High School Burlington-Edison Burlington 32 62 149 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Central Elementary School Sedro-Woolley Sedro-Woolley 27 58 140 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Clear Lake Elementary School Sedro-Woolley Clear Lake 29 57 137 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Concrete Elementary School Concrete Concrete 17 42 100 Case M LBZ GP Lahar2 GP Lahar2 5,000 1.00% Moderate Concrete High School Concrete Concrete 17 42 100 Case M LBZ GP Lahar2 GP Lahar2 5,000 1.00% Moderate Conway School Conway Mount Vernon 38 58 139 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Edison Elementary School Burlington-Edison Edison 32 69 165 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Jefferson Elementary School Mount Vernon Mount Vernon 35 60 144 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate La Conner Elementary School La Conner La Conner 41 67 160 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate La Conner High School La Conner La Conner 41 67 160 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate La Conner Middle School La Conner La Conner 41 67 160 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Lucille Umbarger Elementary School Burlington-Edison Burlington 32 61 146 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Lyman Elementary School Sedro-Woolley Lyman 21 52 125 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Mary Purcell Elementary School Sedro-Woolley Sedro-Woolley 27 58 140 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Mount Vernon Special Ed Mount Vernon Mount Vernon 35 60 145 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Northwest Career & Technical La Conner La Conner 39 68 162 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Academy - Mount Vernon Campus Sedro Woolley Senior High School Sedro-Woolley Sedro-Woolley 27 58 140 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Skagit Family Learning Center MVSD Mount Vernon Mount Vernon 35 60 145 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Skagit River School House Concrete Concrete 17 42 100 Case M LBZ GP Lahar2 GP Lahar2 5,000 1.00% Moderate Special Services School Concrete Concrete 17 42 100 Case M LBZ GP Lahar2 GP Lahar2 5,000 1.00% Moderate State Street High School Sedro-Woolley Sedro-Woolley 27 58 140 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate Twin Cedars High School Concrete Concrete 17 42 100 Case M LBZ GP Lahar2 GP Lahar2 5,000 1.00% Moderate Washington Elementary School Mount Vernon Mount Vernon 35 61 146 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate West View Elementary School Burlington-Edison Burlington 32 62 149 Case M GP Lahar2 GP Lahar2 5,000 1.00% Moderate 1 Lahars affecting areas near the volcano, such as Darrington. 2 Lahars affecting areas further from the volcano, near Puget Sound.
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Table 9.13 K–12 Facilities within USGS Mapped Volcanic Hazard Zones: Mount Adams
Volcanic Hazard Zones Approximate Distance Return Lahar Zone LB Zone LC Probability Volcanic Hazard Facility Name District City to Peak Governing Period Travel Time Lava Lava Zone DL (Miles) Volcanic in 50 Years Level (Minutes) Pyroclastic Pyroclastic Lahar (Years) Event Tephra Tephra Klickitat Elementary & High School Klickitat Klickitat 31 75 Zone DL Zone DL 30,000 0.17% Very Low Glenwood Elementary School Glenwood Glenwood 16 N/A Zone LB Zone LB 100,000 0.05% Extremely Low Glenwood Secondary Glenwood Glenwood 16 N/A Zone LB Zone LB 100,000 0.05% Extremely Low Trout Lake Elementary School Trout Lake Trout Lake 11 N/A Zone LB Zone LB 100,000 0.05% Extremely Low Trout Lake School Trout Lake Trout Lake 12 N/A Zone LB Zone LB 100,000 0.05% Extremely Low Canyon Creek Middle School Washougal Washougal 20 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Cape Horn Skye Elementary School Washougal Washougal 20 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Carson Elementary School Stevenson-Carson Carson 14 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Columbia High School White Salmon Valley White Salmon 20 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Columbia Technical High School White Salmon Valley White Salmon 20 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Hulan L. Whitson Elementary School White Salmon Valley White Salmon 21 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Kaplan Academy of Washington Stevenson-Carson Stevenson 15 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Mill A Elementary School Mill A Cook 15 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Mount Pleasant Elementary School Mount Pleasant Washougal 23 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Skamania Elementary School Skamania Skamania 18 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Stevenson Elementary School Stevenson-Carson Stevenson 16 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Stevenson High School Stevenson-Carson Stevenson 15 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Wayne M. Henkle Middle School White Salmon Valley White Salmon 21 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low White Salmon Academy White Salmon Valley White Salmon 20 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low Wind River Middle School Stevenson-Carson Carson 14 N/A Zone LC Zone LC 1,000,000 0.005% Extremely Low
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Notes for Table 9.6:
The volcanic hazard levels shown in Table 9.6 are preliminary estimates, based only on the estimated return period for lahars, lava flows, pyroclastic flows, or lateral blasts reaching a given campus. The return periods corresponding to various volcanic hazard levels were shown previously in Tables 9.4 and 9.5. More accurate estimates require additional campus-specific information that is beyond the scope of this statewide assessment. This includes the distance and travel time to safe havens outside of lahar zones and whether there is a lahar warning system.
The estimated lahar travel time to campus is a preliminary estimate only and is based on the straight-line distance from the volcanic peak to the campus with an assumed average lahar velocity of 25 miles per hour. More accurate measurements require determination of the actual travel distance along the flow path and more accurate velocity estimates. Estimated velocities will vary with slope and channel geometry along the lahar path. There are two important caveats on these preliminary travel times: o The travel times are deliberately conservative – actual travel times may be longer because flow path distances are longer than straight line distances and because the flow velocities diminish when lahars reach lower slope areas. o However, warning times may be much shorter than travel times. With a warning system, the estimate time between initiation of a lahar and the issuance of a warning is about 30 minutes. Absent a warning system or other notification that a lahar has been initiated, the only warning of an approaching lahar would be a loud rumbling accompanied by a roaring sound similar to that from a jet or locomotive. The time interval between hearing the approaching lahar and lahar arrival may be only five or ten minutes (or even less).
The estimated return periods are based on USGS estimates where such estimates have been made and on professional judgment where such estimates are not available. In cases where the USGS estimate is a range, rather than a single value, the quoted values are the midpoint of the range.
The K–12 facilities in Table 9.6 are those within the USGS mapped volcanic hazard zones. There may also be other K–12 facilities with lahar risk, especially facilities near the mapped volcanic hazard zones. For example, larger lahars than anticipated may occur and/or temporary debris dams may raise lahar levels upstream and inundate wider areas downstream when they are breached.
9.5 Mitigation of Volcanic Hazards Volcano Monitoring and Volcano Activity Alerts The USGS monitors volcanic activity in the Cascades via networks of seismic sensors (which can detect earthquakes related to magma movements) as well as very accurate ground surface measurements. The USGS also has a volcanic warning and notification system with several levels of alert when a potential eruption becomes more likely and more imminent.
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Figure 9.14 Volcanic Alert Levels for People on the Ground12
Alert Term Description
Volcano is in typical background, noneruptive state or, after a NORMAL change from a higher level, volcanic activity has ceased and volcano has returned to noneruptive background state.
Volcano is exhibiting signs of elevated unrest above known background level or, after a change from a higher level, volcanic ADVISORY activity has decreased significantly but continues to be closely monitored for possible renewed increase.
Volcano is exhibited heightened or escalating unrest with increased WATCH potential of eruption, timeframe uncertain, or eruption is underway but poses limited hazards.
WARNING Hazardous eruption is imminent, underway or suspected.
There is an important caveat on volcanic alerts. Although volcanoes typically show signs of increasing activity such as magma moving upward to shallow levels before an eruption occurs, this is not always the case. A volcano must be adequately monitored for signs of increasing activity to be detected. Furthermore, a volcanic eruption may occur without immediate warning if a volcano suffers an extremely large landslide that suddenly releases the pressure confining the magma. Such a scenario can result in an immediate eruption, as was demonstrated by the May 18, 1980 eruption of Mount St. Helens. Most seismic monitoring systems deployed at Cascade volcanoes can, under some circumstances, detect the movement of large lahars; but there are no warning systems in place to alert downstream communities of approaching lahars except in the case of Mount Rainier. A USGS-designed lahar warning system in the Carbon River and Puyallup River valleys, on the west side of Mount Rainier, is operated by Pierce County. A warning system was developed at Mount Rainier because it poses the highest level of lahar risk based on the combination of frequency of past lahars, the large mass of weak rock making up the upper west flank of the volcano and the very large population within the mapped lahar hazard zones downstream. The operation of the Mount Rainier lahar warning system is described in the following quotation from the USGS website: 13 ”An automated system detects lahar flows by using a network of small sensors called acoustic flow monitors (AFMs) embedded underground to measure ground vibrations made by passing lahars. Computer base stations located in the Washington State Emergency Operations Center (EOC) continuously analyze signals from the field stations. Upon detection of a lahar, the computer alerts local 24–hour emergency monitoring and notification centers, who initiate the warning component of the system. Warning messages would trigger immediate, preplanned emergency-response actions.
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Know how to respond to a lahar warning.
Residents, employees, and visitors in lahar–hazard areas will be notified of an approaching lahar through multiple channels of communication. Many schools and other public and commercial facilities will receive notice directly from the EOC, television and radio stations, as well as NOAA Weather Radio, will broadcast warnings on the Emergency Alert System. A system of All Hazard Alert Broadcast (AHAB) sirens in cities and towns from Orting to the Port of Tacoma will provide evacuation alerts regarding the lahar and protective measures. Check with local officials to find out what is available in your community, school, or workplace.
Once people in the Puyallup and Carbon River valleys receive a lahar warning, they need to respond effectively. Pierce County and the State of Washington agencies have developed an evacuation plan with marked evacuation routes to aid residents and visitors. Parts of some communities rely on evacuation by foot to high ground, especially in areas where highways may become clogged with traffic.
In at-risk areas too remote to receive notification by one of the above methods, it is necessary to be aware of the natural warning signs of an approaching lahar—ground rumbling accompanied by a roaring sound similar to a jet or locomotive. Moving to high ground immediately is the recommended course of action.” Volcanic Hazard Mitigation Measures There are no physical measures that are practical from either an engineering perspective or an economic perspective to prevent lahars, lateral blasts, or ash falls from affecting a campus. The following mitigation measures are suggested for districts with facilities in or near mapped lahar and lateral blast zones:
Ensure Awareness. Ensure that staff and students are aware of the lahar hazards.
Emergency Planning. Develop and practice an effective emergency evacuation plan with designated evacuation methods, evacuation routes, and pre-determined safe haven gathering locations.
Develop Criteria. Develop contingency plans and decision-making criteria for district actions if a volcano is showing signs of increased activities. For campuses within mapped volcanic hazard zones, it is essential to define criteria for which the risk is deemed high enough to warrant proactive evacuation of a campus before volcanic activity occurs.
Location Avoidance. Whenever possible, avoid building new facilities in or near mapped lahar zones.
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The following mitigation measures are suggested for districts located within the higher probability ash fall areas as shown previously in Figure 9.9:
Ensure Awareness. Ensure that staff and students are aware of ash fall hazards, especially when a volcano is showing signs of increased activity.
Emergency Planning. Develop procedures for ash fall events including evacuation criteria, protocols, and procedures for dealing with ash falls affecting district facilities.
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Chapter Ten: Floods
10.1 Introduction Washington State is subject to flooding from several different flood sources:
Overbank flooding from rivers and streams.
Coastal storm surge flooding.
Local stormwater drainage flooding.
Channel migration.
Sheet flow flooding.
Flooding from failures of dams, reservoirs or levees.
Other flood source - subsidence, tsunamis and seiches. Overbank flooding from rivers and streams occur throughout Washington most commonly from winter storms with heavy rainfall during November to February. Flood events with significant contributions from snowmelt may also occur during the spring snowmelt season for watersheds with high enough elevations to have significant snowfalls. Although it is less common, overbank flooding can also occur at any time of the year. The severity of overbank flooding depends primarily on flood depth. However, other factors such as flood duration, flow velocity, debris loads, and contamination with hazardous materials also significantly impact the severity of any given flood event. Overbank flooding can be very severe and affect broad geographic areas.
Figure 10.1 Chehalis River Flood in Centralia, Washington–December 20071
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Coastal storm surge flooding affects low elevation areas along the coasts of the Pacific Ocean, Puget Sound and Strait of Juan de Fuca. It is most common from winter storm events which generally occur from November through February. Coastal flooding results from the combination of storm-driven surges and daily tides. Maximum flooding occurs when the peaks of storm- driven surges coincide with high tides. The severity of coastal flooding depends not only on flood depths but also on wave effects and debris impacts. Wave pounding exerts substantial forces on structures, and extended ponding by frequent waves may destroy structures not designed to withstand wave forces. Wave action may also destroy structures by erosion (scour) that undermines foundations. Debris impacts may greatly increase damages for a given flood depth. Figure 10.2 illustrates storm surge effects.
Figure 10.2 Storm Surge Effects
Coastal flood events are expected to become more frequent and more severe in the future because of global warming and sea level rise. A consensus of climate scientists currently estimate2 that the sea level may gradually rise by about 1.4 to 2.0 meters (4.6 to 6.2 feet) over the next hundred years. Sea level rise is also expected to exacerbate beach erosion that may further increase flooding potential in coastal areas. Storm water drainage flooding, sometimes referred to as urban flooding, occurs when inflow of storm water exceeds the conveyance capacity of a local storm water drainage system. The drainage system overflows, resulting in water ponding in low lying areas. This type of flooding is generally localized with flood depths that may range from a few inches to several feet. Channel migration flooding occurs when ongoing erosion/deposition on the banks of a river result in the channel of a river or stream migrating (moving) to an extent that structures are affected by floods. Rivers or streams with low gradients (flat topography) and meandering patterns are prone to channel migration. Sheet flow flooding occurs when stream flows are not confined to a channel but occur over a broad area. Sheet flows are common in areas within alluvial fans, which are sloping accumulations of sediments eroded from mountains or hills. Failures of dams, reservoirs for potable water systems or levees, result in flooding areas downstream of dams and reservoirs or behind levees. Failures of major dams, operated and
Page | 176 regulated by state or federal agencies, are possible but unlikely because these dams are generally well-designed and well-maintained. However, failures of smaller dams maintained by local governments, special districts, or private owners are more common. Failures of reservoirs for potable water systems occur, especially from earthquakes. These reservoirs typically have much smaller storage volumes than dams, so flooding from failures is generally localized, but may be severe where flows are confined in narrow channels which contain structures or infrastructure. Similar flooding may occur from failures of large diameter water pipes. Levee failures before overtopping may occur at any time, not only during high water events but also under normal non-flood conditions. There are numerous causes for such failures including scour, foundation failures, under-seepage, through-seepage, and animal burrows etc. Failures of major levees, such as those along the Columbia River, are possible because most major levees are well-designed and well-maintained. However, some levees on the Upper Columbia River and major tributaries have been identified as having significant vulnerabilities. Failures of smaller levees maintained by local governments, drainage districts, irrigation districts or private owners are more common. Flooding from other sources may also occur including subsidence, tsunamis and seiches. Major earthquakes on the Cascadia Subduction Zone are expected to result in coastal subsidence of several feet. This subsidence will result in flooding of low elevation areas. Further details about earthquakes on the Cascadia Subduction Zone are provided in Chapter Seven Earthquakes. Cascadia Subduction Zone earthquakes will also generate tsunamis that will cause widespread inundation and heavy damage for low-elevation areas along coastal areas on the Pacific Ocean and Puget Sound. Tsunamis within Puget Sound may also be generated by earthquakes on the Seattle Fault Zone or the Tacoma Fault Zone. Earthquakes may also generate seiches in inland bodies of water. Seiches, which are waves from sloshing of water in lakes or rivers, may result in inundation and significant damages to harbor and dock facilities as well as buildings at low elevations near the shoreline. Further details about tsunamis and seiches are provided in Chapter Eight Tsunamis.
10.2 Washington State Floods Overview Historically, flooding has occurred in Washington State throughout recorded history. The most severe, widespread flood events occurred:
May/June 1948 with widespread flooding in Eastern Washington and along the Columbia River from spring snowmelt.
November 1990 with widespread flooding on Western Washington rivers as well as several Eastern Washington rivers. This event was the flood of record, the greatest recorded flood, on many rivers in Northwest Washington.
February 1996 with major flooding on many rivers in Western and Southeastern Washington. This event was the flood of record on many rivers in Southwest Washington.
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January 2012 with major flooding in Western Washington. This event was the flood of record on some rivers. Every county in Washington is subject to flood risk and has experienced major flood events. However, Western Washington has experienced more major flood events than Eastern Washington. Presidential Disaster Declarations provide a good indicator of the frequency of major flooding in Washington. Since 1956, there have been 36 Presidential Disaster Declarations for flooding.3
Figure 10.3 Frequency of Presidential Disaster Declarations for Flooding3
The counties in Western Washington shown in red or orange above have had the most frequent major flood events with average return periods of five years or less. The frequency of major flooding is correlated with precipitation levels. Figure 10.3 shows 100-year, 24-hour precipitation data. The high precipitation areas shown in blue and green on Figure 10.3 include all of the counties with a history of frequent major flood events.
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Figure 10.4 100-Year, 24-Hour Precipitation4
The previous maps give a general idea of the likelihood of flooding from county to county. However, within any given county the level of flood risk varies dramatically with location:
Many locations in the counties with the highest rainfall and most historical flood events have low or negligible flood risk.
Some locations in the counties with the lowest precipitation and the fewest historical flood events have very high flood risk. For a facility at any given location, flood risk depends on the location relative to flood sources, the facility elevation relative to potential flood elevations, the facility value and importance, and its vulnerability to flood damages. FEMA’s floodplain mapping, discussed in the following section, provides a good starting point for flood risk assessments. Facilities within FEMA mapped floodplains have at least some level of flood risk. However, determining the level of risk quantitatively requires additional flood hazard data, including the elevation of facilities relative to the elevation of a range of flood events. It is also important to recognize that some facilities not within FEMA-mapped floodplains also have high levels of flood risk.
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10.3 FEMA-Mapped Floodplains FEMA Flood Insurance Rate Maps (FIRMs) delineate the regulatory (100-year) floodplain areas in Washington. Per FEMA regulations, there are limitations on new development within the 100-year floodplain. Figure 10.4 on the following page shows the FEMA-mapped floodplains in Washington. Most FEMA-mapped floodplains are small, narrow areas that are difficult or impossible to show on statewide or regional maps. High resolution floodplain maps, known as Firmettes, can be created to show floodplains for individual schools. An example for the A. J. West Elementary School in Aberdeen is shown in Figure 10.5. FEMA floodplain maps represent the best available data at the time the maps were prepared. FEMA has an ongoing map modernization/update process, but many existing FIRM maps are old (some more than 30 years old). Over time watersheds evolve; therefore, floodplain boundaries and the quantitative flood hazard data discussed in the following section may change over time. In many cases, flood risk in a given location increases with time because increasing development within the watershed increases runoff. Also, development and fill within floodplains, or sedimentation in a river channel, may increase flood elevations. In some cases, flood elevations for a 100-year flood using current data may be up to several feet higher than outdated floodplain maps indicate. Flood risk at a given location may also decrease over time if flood control structures, such as levees or upstream dams for flood control, are constructed or improved. Old floodplain maps are not necessarily incorrect. However, older maps should be interpreted carefully because the older a map is the more likely it is to be significantly incorrect. Recent and future FEMA floodplain maps are available in digital GIS-format and are known as DFIRMs. Older maps, which were originally prepared in paper format only, have been digitized but contain less detailed information than DFIRMs. These maps are known as Q3 maps. For any given location, the most recent FEMA maps should be used for flood risk assessments.
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Figure 10.5 FEMA-Mapped Floodplains in Washington State
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Figure 10.6 FEMA Firmette for A.J. West Elementary School in Aberdeen
A. J. West Elementary School
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FEMA floodplain regulations apply within the mapped 100-year floodplain boundary. Thus, the FEMA floodplain maps always delineate the 100-year floodplain boundary. The 100-year flood is defined probabilistically. A 100-year flood does not occur exactly every 100 years. Rather, the 100-year flood is the flood with a one percent chance of being exceeded in any given year. A one percent annual chance of flooding corresponds to about a 26 percent chance of flooding in a 30-year time period. A given location may have two or more 100-year (or greater) flood events within a few years, have none in several decades, or none in periods longer than 100 years. FEMA floodplain maps identify several types of flood zones, with varying levels of flood hazard. The FEMA flood zone designations have evolved over time, with older maps using different nomenclature than recent maps. FEMA flood zone designations are summarized below.
Table 10.1 High Risk Areas
ZONE DESCRIPTION
Areas with a one percent annual chance of flooding and a 26 percent chance of A flooding over 30 years. Because detailed analyses are not performed for such areas, no depths or base flood elevations are shown within these zones.
The base floodplain where base flood elevations are provided. AE Zones are AE, A1 – A30 used on recent FIRMs instead of A1–A30 Zones. Areas with a one percent annual chance of shallow flooding, usually in the form of a pond, with an average depth ranging from one to three feet. These AH areas have a 26 percent chance of flooding over 30 years. Base flood elevations derived from detailed analyses are shown at selected intervals within these zones. River or stream flood hazard areas and areas with a one percent or greater chance of shallow flooding each year, usually in the form of sheet flow, with an AO average depth ranging from one to three feet. These areas have a 26 percent chance of flooding over 30 years. Average flood depths derived from detailed analyses are shown within these zones. Areas with a temporarily increased flood risk due to the building or restoration AR of a flood control system (such as a levee or a dam). Areas with a one percent annual chance of flooding that will be protected by a A99 Federal flood control system where construction has reached specified legal requirements. No depths or base flood elevations are shown within these zones.
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Table 10.2 High Risk Coastal Areas
ZONE DESCRIPTION Coastal areas with a one percent or greater chance of flooding and an additional hazard associated with storm waves. These areas have a 26 V percent chance of flooding over 30 years. No base flood elevations are shown with these zones. Coastal areas with a one percent or greater chance of flooding and an additional hazard associated with storm waves. These areas have a 26 VE, V1 – V30 percent chance of flooding over 30 years. Base flood elevations derived from detailed analysis are shown at selected intervals within these zones. VE Zones are used in recent FIRMs, instead of V1–V30 Zones.
Table 10.3 Moderate to Low Risk Areas
ZONE DESCRIPTION Area of moderate flood hazard, usually the area between the limits of the 100-year and 500-year floods. B Zones are also used to designate base B and X (shaded) floodplains of lesser hazards such as areas protected by levees from 100-year flood, or shallow flooding areas with average depths of less than one foot or drainage areas less than one square mile. Area of minimal flood hazard, usually depicted on FIRMs as above the 500-year flood level. Zone C may have ponding and local drainage C and X problems that don't warrant a detailed study or designation as base (unshaded) floodplain. Zone X is the area determined to be outside the 500-year flood and protected by levee from 100-year flood.
Table 10.4 Undetermined Risk Areas
ZONE DESCRIPTION Areas with possible but undetermined flood hazards. No flood hazard D analysis has been conducted. Flood insurance rates are commensurate with the uncertainty of the flood risk.
FEMA Flood Insurance Rate Maps are always accompanied by Flood Insurance Studies. Flood Insurance Studies contain summaries of historical floods, details of the flood mapping and quantitative flood hazard data which is essential for quantitative flood risk assessments.
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FEMA Flood Insurance Studies and Flood Insurance Rate Maps include a large number of terms of art and acronyms. A good summary of the terms used in flood hazard mapping is available from FEMA.5
10.4 Campuses within FEMA-Mapped Floodplains The OSPI listing of K–12 facilities in Washington includes 2,427 active campuses as of late 2012. Of these, 169 campuses identified as being located within FEMA-mapped floodplains are listed in Table 10.5 on the following pages. There are several caveats regarding interpretation of the list of campuses located within FEMA- mapped floodplains:
The identification of campuses as being located within FEMA-mapped 100-year floodplains is based on the latitude-longitude data in the OSPI database. Small errors in latitude-longitude may result in misidentification of a campus as being in or out of mapped floodplains.
Some campuses may be partially within and partially outside of mapped floodplains. A single latitude-longitude point for each campus is not adequate to determine such cases.
Final determination of the relationship of each campus to mapped floodplains and determining the specific FEMA flood zone that applies to a given campus requires campus-by-campus evaluations including review of the FEMA Flood Insurance Rate Map or FEMA Firmette for each campus, including those near, but not identified as within mapped floodplains.
Floods significantly larger than the 100-year flood do occur.
A determination that a campus is not within a FEMA-mapped floodplain does not necessarily mean that a campus has no flood risk. Campuses outside of mapped floodplains may have significant risk, even high risk in the following circumstances: o The river or stream near a campus has not been mapped by FEMA. o The FEMA floodplain mapping is old, and the stream and/or watershed conditions have significantly changed over time. o Flood risk from local stormwater drainage problems rather than overbank or coastal flooding. FEMA floodplain maps do not consider local stormwater drainage problems. o A campus is downstream of dams or reservoirs or located behind levees. o Debris dams or beaver dams may result in ponding and flooding upstream and/or downstream flooding if such dams fail suddenly.
It is important to include evaluation of non-FEMA mapped flood sources for campuses with any of the characteristics in the preceding bullet or with a history of flood events, during the development of a district hazard mitigation plan.
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Table 10.5 Campuses within FEMA Mapped Flood Plains
FACILITY INFORMATION FLOOD HAZARDS GIS FEMA Campus Facility Name District City Map Flood Elevation At Source Zone Grade Feeta A.J. West Elementary School Aberdeen Aberdeen Q3 A 9.84 Harbor High School Aberdeen Aberdeen Q3 A 11.15 Hopkins Preschool Center Aberdeen Aberdeen Q3 A 10.83 Miller Junior High School Aberdeen Aberdeen Q3 A 22.97 Stevens Elementary School Aberdeen Aberdeen Q3 A 24.93 Alexander Young Elementary Aberdeen Aberdeen Q3 A 18.70 Asotin Elementary School Asotin-Anatone Asotin Q3 X500 765.08 Asotin Junior Senior High School Asotin-Anatone Asotin Q3 X500 761.80 Brinnon Elementary School Brinnon Brinnon Q3 A 22.64 Allen Elementary School Burlington-Edison Bow Q3 X500 19.68 Burlington-Edison Alternative School Burlington-Edison Burlington Q3 A 29.86 Burlington-Edison High School Burlington-Edison Burlington Q3 A 28.21 Edison Elementary School Burlington-Edison Edison Q3 A 1.97 Lucille Umbarger Elementary School Burlington-Edison Burlington Q3 A 32.15 West View Elementary School Burlington-Edison Burlington Q3 A 26.57 Vale Elementary School Cashmere Cashmere DFIRM X500 828.73 Castle Rock Elementary School Castle Rock Castle Rock Q3 X500 49.87 Castle Rock High School Castle Rock Castle Rock Q3 X500 49.87 Castle Rock Middle School Castle Rock Castle Rock Q3 X500 49.87 Productive Learning Online Castle Rock Castle Rock Q3 X500 49.87 Centralia High School Centralia Centralia Q3 X500 163.71 Oakview Elementary School Centralia Centralia Q3 A 193.90 Green Hill Academic School Chehalis Chehalis Q3 A 183.72 Chewelah Alternative Chewelah Chewelah Q3 AE 1667.63 Home Link Alternative Chewelah Chewelah Q3 AE 1667.63 Cedar Program Coupeville Coupeville DFIRM AE 6.89 Dayton High School Dayton Dayton Q3 X500 1619.73 Trentwood Elementary School East Valley (Spokane) Spokane Valley DFIRM X500 2030.82 Cascade Elementary School Eastmont East Wenatchee Q3 X500 843.17 Clovis Point Intermediate School Eastmont East Wenatchee Q3 X500 988.51 Eastmont Columbia Virtual Academy Eastmont East Wenatchee Q3 X500 785.10 Eastmont Junior High School Eastmont East Wenatchee Q3 X500 941.92 Eastmont Senior High School Eastmont East Wenatchee Q3 X500 862.52 Grant Elementary School Eastmont East Wenatchee Q3 X500 925.19 Kenroy Elementary School Eastmont East Wenatchee Q3 X500 987.52 Robert E Lee Elementary School Eastmont East Wenatchee Q3 X500 778.86 Rock Island Elementary School Eastmont Rock Island Q3 X500 654.52 Sterling Intermediate School Eastmont East Wenatchee Q3 X500 961.27 Ellensburg Developmental Preschool Ellensburg Ellensburg Q3 X500 1563.30 Excel High School Ellensburg Ellensburg Q3 X500 1563.30 Morgan Middle School Ellensburg Ellensburg Q3 X500 1526.56 Washington Elementary School Ellensburg Ellensburg Q3 X500 1550.83 Elma Elementary School Elma Elma Q3 X500 51.84 Enumclaw Middle School Enumclaw Enumclaw Q3 A 724.40 Thunder Mountain Middle School Enumclaw Enumclaw Q3 A 685.03 Beezley Springs Elementary School Ephrata Ephrata DFIRM AO 1270.65 Ephrata High School Ephrata Ephrata DFIRM AO 1272.95 Grant Elementary School Ephrata Ephrata DFIRM AO 1276.56 Parkway School Ephrata Ephrata DFIRM AO 1258.51 Central Elementary School Ferndale Ferndale DFIRM AE 26.57 North Bellingham Elementary Ferndale Ferndale DFIRM AE 9.84 Central Elementary School Hoquiam Hoquiam Q3 A 19.03 Emerson Elementary School Hoquiam Hoquiam Q3 A 17.72 Hoquiam Homelink School Hoquiam Hoquiam Q3 A 9.84 Lincoln Elementary School Hoquiam Hoquiam Q3 A 15.75 Washington Elementary School Hoquiam Hoquiam Q3 A 16.73 Transportation Maintenance Center Hoquiam Hoquiam Q3 A 9.84
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Table 10.5–Continued Campuses within FEMA Mapped Floodplains
FACILITY INFORMATION FLOOD HAZARDS GIS FEMA Campus Facility Name District City Map Flood Elevation At Source Zone Grade Feeta Barnes Elementary School Kelso Kelso Q3 X500 20.01 Catlin Elementary School Kelso Kelso Q3 X500 31.50 Coweeman Middle School Kelso Kelso Q3 X500 11.81 Huntington Middle School Kelso Kelso Q3 X500 20.01 Kelso High School Kelso Kelso Q3 X500 11.81 Wallace Elementary School Kelso Kelso Q3 X500 16.73 Mill Creek Middle School Kent Kent Q3 X500 45.28 Kent Junior High School Kent Kent Q3 X500 44.95 Kittitas B-5 Special Education Program Kittitas Kittitas Q3 A 1654.51 La Center Elementary School La Center La Center Q3 A 82.02 Northwest Career & Technical Academy - La Conner La Conner Q3 A 1.64 Mount Vernon Campus La Conner Elementary School La Conner La Conner Q3 A 5.25 La Conner High School La Conner La Conner Q3 A 5.58 La Conner Middle School La Conner La Conner Q3 A 4.27 Ready Start Preschool Lake Washington Redmond Q3 A 32.81 Broadway Learning Center Longview Longview Q3 X500 18.04 Columbia Valley Garden Elem School Longview Longview Q3 X500 12.80 Kessler Elementary School Longview Longview Q3 X500 10.50 Longview School District. Special Services Longview Longview Q3 X500 19.03 Mark Morris High School Longview Longview Q3 X500 16.73 Mint Valley Elementary School Longview Longview Q3 X500 17.72 Monticello Middle School Longview Longview Q3 X500 10.83 Northlake Elementary School Longview Longview Q3 X500 13.78 Olympic Elementary School Longview Longview Q3 X500 9.84 R. A. Long High School Longview Longview Q3 X500 9.84 Robert Gray Elementary School Longview Longview Q3 X500 19.03 Saint Helens Elementary School Longview Longview Q3 X500 9.84 Harding School Longview Longview Q3 X500 10.83 Longview LSD Administration Longview Longview Q3 X500 19.03 Structured Learning Center Longview Longview Q3 X500 9.84 Decatur Elementary School Lopez Island Anacortes Q3 A 2.30 Fisher Elementary School Lynden Lynden DFIRM AE 66.27 Fryelands Elementary School Monroe Monroe DFIRM X500 29.20 Salem Woods Elementary School Monroe Monroe Q3 X500 320.53 Sky Valley Education Center Monroe Monroe DFIRM X500 39.37 Acme Elementary School Mount Baker Acme DFIRM X500 317.58 Jefferson Elementary School Mount Vernon Mount Vernon Q3 A 18.04 Mount Vernon Special Ed Mount Vernon Mount Vernon Q3 A 25.92 Skagit Family Learning Center MVSD Mount Vernon Mount Vernon Q3 A 15.09 Washington Elementary School Mount Vernon Mount Vernon Q3 A 19.68 Nooksack Valley Middle School Nooksack Valley Everson DFIRM AE 83.66 Nooksack Valley Connections Nooksack Valley Everson DFIRM X500 85.30 Sumas Elementary School Nooksack Valley Sumas DFIRM AE 34.78 North Mason Senior High School North Mason Belfair Q3 A 200.13 Kenmore Elementary School Northshore Kenmore Q3 A 46.59 Long Beach Elementary School Ocean Beach Long Beach Q3 X500 8.20 Ocean Beach Early Childhood Center Ocean Beach Long Beach Q3 X500 8.86 Okanogan Alternative High School Okanogan Okanogan Q3 X500 830.04 E Omak Elementary School Omak Omak Q3 X500 834.96 Omak Alternative High School Omak Omak Q3 X500 835.95 Omak High School Omak Omak Q3 X500 846.77 Oroville Elementary School Oroville Oroville Q3 X500 928.14 Orting High School Orting Orting Q3 X500 178.80 Palisades Elementary School Palisades Palisades Q3 A 985.22 Pioneer Intermediate Middle School Pioneer Shelton Q3 A 196.85 Pomeroy Elementary School Pomeroy Pomeroy Q3 AE 1860.87
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Table 10.5–Continued Campuses within FEMA Mapped Floodplains
FACILITY INFORMATION FLOOD HAZARDS GIS FEMA Campus Facility Name District City Map Flood Elevation At Source Zone Grade Feeta Pomeroy Junior Senior High School Pomeroy Pomeroy Q3 X500 1859.89 Riverside Elementary School Puyallup Puyallup Q3 X500 20.01 Shaw Road Elementary School Puyallup Puyallup Q3 A 76.44 Queets-Clearwater Elementary Queets-Clearwater Forks Q3 A 26.25 Developmental Preschool Raymond Raymond Q3 A 8.86 Raymond Elementary School Raymond Raymond Q3 A 8.86 Raymond Home Link School Raymond Raymond Q3 A 8.86 Raymond Junior Senior High School Raymond Raymond Q3 A 8.86 Seward Elementary School Seattle Seattle Q3 X500 127.30 Clear Lake Elementary School Sedro-Woolley Clear Lake Q3 A 43.96 Mary Purcell Elementary School Sedro-Woolley Sedro-Woolley Q3 X500 47.90 Skykomish Elementary School Skykomish Skykomish Q3 A 923.87 Skykomish High School Skykomish Skykomish Q3 A 924.20 Centennial Middle School Snohomish Snohomish Q3 A 90.88 Riverview Elementary School Snohomish Snohomish DFIRM AE 5.25 Mount Si High School Snoqualmie Valley Snoqualmie Q3 A 420.27 North Bend Elementary School Snoqualmie Valley North Bend Q3 X500 445.86 Snoqualmie Access Snoqualmie Valley Snoqualmie Q3 A 414.37 Snoqualmie Elementary School Snoqualmie Valley Snoqualmie Q3 A 410.10 Snoqualmie Middle School Snoqualmie Valley Snoqualmie Q3 A 410.10 Two Rivers School Snoqualmie Valley North Bend Q3 X500 440.94 Chauncey Davis Elementary School South Bend South Bend Q3 A 17.39 South Bend High School South Bend South Bend Q3 A 16.73 Sheridan Elementary School Spokane Spokane DFIRM X500 1919.92 Saratoga School Stanwood-Camano Stanwood Q3 A 5.91 Stanwood Elementary School Stanwood-Camano Stanwood Q3 A 5.58 Stanwood Middle School Stanwood-Camano Stanwood Q3 A 7.87 Toledo Alternative Options Toledo Toledo Q3 A 119.75 Toledo Elementary School Toledo Toledo Q3 A 103.67 Toledo Middle School Toledo Toledo Q3 A 139.11 Garfield Elementary School Toppenish Toppenish Q3 X500 756.88 Kirkwood Elementary School Toppenish Toppenish Q3 X500 763.11 Lincoln Elementary School Toppenish Toppenish DFIRM AE 756.22 Toppenish Middle School Toppenish Toppenish DFIRM AE 759.51 Toppenish Pre School Toppenish Toppenish Q3 X500 763.11 Valley View Elementary School Toppenish Toppenish DFIRM AE 757.54 Waitsburg Elementary School Waitsburg Waitsburg Q3 A0 1269.67 Waitsburg High School Waitsburg Waitsburg Q3 AE 1258.84 Abraham Lincoln Elementary School Wenatchee Wenatchee Q3 X500 813.31 Columbia Elementary School Wenatchee Wenatchee Q3 X500 785.75 Foothills Middle School Wenatchee Wenatchee Q3 X500 715.21 John Newbery Elementary School Wenatchee Wenatchee Q3 A 840.21 Lewis and Clark Elementary School Wenatchee Wenatchee Q3 X500 705.04 Mission View Elementary School Wenatchee Wenatchee Q3 X500 745.73 Orchard Middle School Wenatchee Wenatchee Q3 X500 745.40 Pioneer Middle School Wenatchee Wenatchee Q3 A 808.06 Valley Academy Of Learning Wenatchee Wenatchee Q3 X500 692.25 Washington Elementary School Wenatchee Wenatchee Q3 A 828.07 Westside High School Wenatchee Wenatchee Q3 A 782.80 Westside Alternative High School Wenatchee Wenatchee Q3 X500 776.89 Ahtanum Valley Elementary School West Valley (Yakima) Yakima DFIRM AE 1321.18 TEAM High School Woodland Woodland Q3 X500 31.17 Woodland High School Woodland Woodland Q3 X500 27.89 Woodland Intermediate School Woodland Woodland Q3 X500 31.82 Woodland Administration Office Woodland Woodland Q3 X500 26.90 Yelm Middle School Yelm Yelm DFIRM AE 329.72
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Footnote for Table 10.5 above: aElevation relative to NAVD 1988 reference datum, from GIS data.
10.5 Flood Hazard Data The level of flood hazard (frequency and severity of flooding) for a given campus or building is not simply determined by whether the campus or building is, or is not, within the mapped 100-year floodplain. Rather, the level of flood hazard depends very strongly on the elevation of buildings relative to the elevation of various flood events such as the 10-year, 50-year or 100-year flood event. For example, consider two schools both within the 100-year floodplain of a given river. The first school has a first floor elevation three feet above the 100-year flood elevation and the level of flood hazard is low (but not zero). The second school has a first floor, elevation three feet below the 100-year flood elevation, and the level of flood hazard is high. In this example, the six foot difference in elevations of the two schools makes an enormous difference in the level of flood hazard. Quantitative evaluation of the level of flood hazard for a given building requires comparison of the building’s first floor elevation relative to the elevation of various flood events For FEMA-mapped 100-year floodplain areas (AE Zones), the flood hazard data included in the Flood Insurance Study (FIS) allows quantitative calculation of the frequency and severity of flooding for any property within the floodplain.
Table 10.6 Flood Hazard Data Example Chehalis River at Confluence with Skookumchuck River
Flood Frequency Discharge Flood Elevation (Years) (cfs)a (feet)
10 45,084 172.8 50 65,410 175.0 100 75,084 176.3 500 100,333 179.5
a Discharge is the volume of water flowing in a river in cubic feet per second
The stream discharge data shown above are from Table 13 on page 34 of the Flood Insurance Study for Lewis County, Washington (November 11, 2010). The flood elevation data are from the Flood Profile Graph 16P also in the Flood Insurance Study. Flood elevations vary with location along the reach of a river. Thus, for any given location along the river, flood elevation data must be read from the flood profile graph covering the location.
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Quantitative flood hazard data, as shown above, are important for mitigation planning purposes because they allow more exact, engineering-based determinations of the frequency and severity (i.e. depth) of flooding for any building: the annual probability of floods of every depth. These types of quantitative flood hazard data are also necessary for benefit-cost analysis of flood mitigation projects. Benefit-cost analysis is a powerful tool to help prioritize between competing mitigation projects and is required for nearly all FEMA mitigation grants. Quantitative flood hazard analysis, in areas subject to coastal flooding, is conceptually very similar to that discussed previously for riverine flooding with one major difference. For coastal flooding, there are no discharge data. Rather, flood hazards are expressed in terms of flood elevations and wave heights. Evaluating flood hazards and flood risk in coastal areas requires more engineering experience and judgment than interpreting the flood data in mapped riverine floodplains. In coastal areas, wave heights and surge velocities are important parameters that increase damage levels. A risk analysis for a given facility must include evaluation of the capacity of the facility to withstand wave and velocity forces as well as the vulnerability of the facility to damage from erosion or scour The Mitigation Planning Toolkit has more detailed guidance and templates to gather and use the types of flood hazard data discussed above.
10.6 Flood Hazards and Flood Risk Outside of Mapped Floodplains The flood hazard data discussed previously is applicable only for locations within FEMA- mapped floodplains or for locations where local hydrologic and hydraulic studies of rivers or streams provide similar quantitative data. Nationwide, more than 25 percent of flood damage occurs outside of FEMA-mapped floodplains. There are many flood-prone areas in Washington outside of FEMA-mapped floodplains, including locations streams too small to be mapped by FEMA and areas subject to localized storm water drainage flooding. For flood-prone locations without quantitative flood hazard data, a different approach is required to evaluate flood hazards and flood risk. There are several possible options:
For high value facilities where flood risk appears high, it may be worthwhile to have a local hydrologic and hydraulic study completed to obtain the types of quantitative flood hazard data contained in a FEMA Flood Insurance Study. Such local studies may also be worthwhile when the FEMA Flood Insurance Study is old and there are reasons, such as increased development in the watershed, to suspect that flood hazards may have significantly increased.
For locations with a history of flooding, empirical estimates of the frequency and severity of flooding may be made from historical data.
For locations subject to stormwater drainage flooding, engineers knowledgeable about the stormwater system may be able to provide quantitative data on the conveyance
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capacity of the system to supplement historical flood data. Stormwater systems are often designed to handle only two-year or five-year flood events, and are infrequently designed to handle rainfall events greater than ten-year or 15-year events. Evaluation of flood hazards and flood risk outside of mapped-floodplains necessarily requires more engineering experience and judgment than are required to interpret the flood data in mapped riverine floodplains.
Dam, Reservoir, and Levee Failures In addition to the flood sources discussed above, many locations in Washington are subject to flooding from dam, reservoir or levee failures. Dams There are about 75 large dams and numerous smaller dams on the Columbia River and its tributaries that provide hydroelectric power, water for many purposes and flood control. A full analysis of the design and safety levels vis-à-vis floods, earthquakes and other hazards for all of these dams is well beyond the scope of this mitigation planning effort. For reference, Figure 10.7 shows some of the major dams in the Columbia River watershed. Many of the larger dams have inundation maps showing the areas of inundation if the dams were to fail. The Washington Department of Ecology Inventory of Dams6 lists 1,149 dams in Washington with ten acre-feet or more of water storage capacity. This very useful inventory lists the storage capacity, dimension, location, purpose, type and other information. This dam inventory also lists the downstream hazard for life safety based on the number of people at risk if a dam were to fail. The six ranges of lives at risk are: none, 1–6, 7–30, 31–300 and >300. These rankings are not risk assessments; that is, there is no determination of safety deficiencies or the probability of failure associated with these rankings. These rankings reflect only the population exposed to inundation if a dam were to fail. The Washington Department of Ecology7 also periodically reports the status of dams with high and significant hazard with safety deficiencies. As of March 2011, the status of 209 dams with identified safety deficiencies was as follows:
171 dams – deficiencies fully corrected.
11 dams – partial repairs completed.
19 dams – engineering studies and/or design work underway.
Eight dams – no actions taken.
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Figure 10.7 Dams in the Columbia River Watershed8
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Reservoirs At grade or elevated water reservoirs for potable water systems or industrial water storage are potential flood sources if they fail during earthquakes or for any other reason. The storage capacity of many water reservoirs is small, but larger reservoirs have higher storage capacities than the ten acre-feet cutoff for the Department of Ecology’s Inventory of Dams.3 For example, a ten million gallon reservoir holds about 30 acre-feet of water. Failure of large capacity reservoirs may result in significant flooding downslope from the reservoir. Floods from reservoir failures are typically restricted to the immediate downslope areas. Especially when the flow path is a narrow area, structures within the flow path may suffer major damage or be destroyed. Levees Many locations in Washington are protected from flooding by levees. Large levees, such as those along the Columbia River, are generally well-engineered and often well-maintained. However, there are also numerous smaller levees owned and maintained by public entities such as counties, cities, irrigation or flood control districts or private owners. These levees range from non- engineered structures built decades ago for agricultural or other purposes to modern, engineered, well-designed structures. The major levees may be accredited by FEMA to provide at least 100-year protection which means that they have a low probability of failure up to at least a 100-year flood event. Most small levees are not accredited, and their level of protection is generally unknown. Many of these levees likely have levels of protection significantly less than the 100-year event while others may have levels of protection comparable to the major levees.
Risk Assessments for Dam, Reservoir, and Levee Failures Risk assessments of dams, reservoirs and levees requires detailed engineering analyses of their structural design and condition by engineers experienced with such evaluations. Undertaking such risk assessments is outside the expertise or responsibility of school districts. Therefore, for mitigation planning purposes; risk assessments for dams, reservoirs and levees focus mainly on determining whether there are any such water storage facilities upstream or upslope from a given campus. If so, then further analysis is likely limited to obtaining existing risk reports if available. For campuses with large volume water storage facilities upstream or upslope; awareness of such facilities, awareness of warning systems and protocols for possible failures, and evacuation planning for possible failures in a school district’s emergency plan are warranted.
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10.7 Flood Scenario Loss Estimates Methods FEMA’s HAZUS loss estimating software has the capability to generate loss estimates for scenario floods such as a 100-year flood. HAZUS for floods uses neither the FEMA Flood Insurance Rate Maps nor the quantitative flood hazard data in FEMA Flood Insurance Studies. Rather, HAZUS makes independent estimates based on digital elevation data and approximate hydrologic and hydraulic modeling of watersheds. The accuracy of HAZUS flood loss estimates is limited by the horizontal and vertical resolution of the digital elevation data and by the simplified hydrologic and hydraulic modeling of watersheds. A HAZUS calculation for a scenario statewide 100-year flood event yielded results that were discordant with the FEMA floodplain mapping. There was almost no correlation between the HAZUS results and the FEMA floodplain-mapping. For example, of the 169 campuses within FEMA-mapped floodplains, only 12 were identified by HAZUS as flooding in a 100-year flood event. Furthermore, many campuses identified as flooding in a 100-year event by HAZUS were well outside of mapped floodplains and/or at high elevations relative to the flood sources. The FEMA floodplain mapping is generally based on higher resolution, more accurate data and is likely to be more accurate than the simplified HAZUS methodology. Therefore, HAZUS results are not presented here and scenario flood loss estimates are based on FEMA data as discussed below. Scenario loss estimates for a hypothetical statewide 100-year flood event were calculated for the 168 campuses within FEMA-mapped floodplains (previously listed in Table 10.5). A statewide 100-year flood event is not realistic. For any given flood event, precipitation, snowmelt and runoff characteristics will vary from watershed to watershed. The purpose of selecting the statewide 100-year flood event is simply to explore the approximate level of damages to K–12 campuses in a major flood event that affects many areas of Washington.
Statewide 100-Year Flood Scenario Results Loss estimates for a statewide 100-year flood event are calculated from the following input data and assumptions:
The square footage of campus buildings from OSPI records. For campuses without data, square footages were estimated as the average square footage for elementary schools and other school facilities, middle schools and high schools.
Building replacement values per square foot were estimated from OSPI data as $272.99 for elementary schools and other facilities, $316.50 for middle schools and $277.20 for high schools.
Contents replacement values per square foot were estimated from insurance data as $12 for elementary schools and other facilities, $14 for middle schools and $19 for high schools.
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Depth-damage functions, the estimate percentages of building damage and contents damage, and the estimated displacement time were taken from the FEMA Version 4.5.5 Benefit-Cost Analysis Software, with values for schools.
Displacement means that flood damage is severe enough that a building has to be vacated for a period of time while flood damage is repaired. Displacement costs were estimated at $1.50 per square foot per month, plus one-time costs of $1.50 per square foot for round trip moving and other one-time costs. Displacement costs include rental of temporary space, extra transportation costs including staff time, moving costs, set-up costs etc. The aggregated data for the 169 campuses listed in Table 10.5 are shown in Table 10.7.
Table 10.7 Aggregated Values for 169 Campuses
Totals for 169 Estimates Campuses Square Feet 10,150,065
Building Replacement Value $2,850,435,731
Contents Replacement Value $146,874,358
The FEMA depth-damage data (typical damages to buildings and contents) are shown in Table 10.8. Damages are expressed as a percentage of the replacement values of buildings and contents. FEMA data also include “displacement” times and costs.
Table 10.8 FEMA Flood Depth-Damage Functions for Schools
Flood Depth Building Contents Displacement (Feet)a Damageb Damagec Time (Days) 0 0.0% 0.0% 0 1 13.0% 22.0% 45 2 21.5% 30.0% 90 3 26.7% 39.0% 135 4 32.7% 45.0% 180 5 36.2% 48.0% 225 a Flood depth relative to first floor. For example, a 1 foot flood means water between 0.5 and 1.5 feet above the first floor.
b Percent of building replacement value
c Percent of contents replacement value
Scenario losses for floods of several depths are shown in Table 10.9.
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Table 10.9 Scenario Loss Estimates: Hypothetical Statewide 100-Year Flood for the 169 Campuses within FEMA-Mapped Floodplains
Flood Depth Building Contents Displacement Total (Feet) Damage Damage Costs 0 $0 $0 $0 $0 1 $370,556,645 $32,312,359 $38,062,745 $440,931,749 2 $612,843,682 $44,062,307 $60,900,392 $717,806,382 3 $761,066,340 $57,281,000 $83,738,039 $902,085,379 4 $932,092,484 $66,093,461 $106,575,686 $1,104,761,632 5 $1,031,857,735 $70,499,692 $129,413,333 $1,231,770,760 The above scenario flood loss results should not be interpreted literally, because a 100-year flood affecting the entire state is not realistic. Rather, these results are intended only to show the approximate levels of damage possible in major, widespread flood events. For example, a flood event that affected one-third of the campuses in Table 10.5 with an average flood depth of one foot would be expected to have damages about one-third of those shown in Table 10.8 for a one foot flood depth. The level of flood risk for a specific campus will vary markedly depending on the elevation of campus buildings relative to flood elevations. Many campuses may have zero damage, even though the campus is within a floodplain, if the first floor elevations of all buildings are well above the flood elevation for a given flood scenario. Other campuses may have some or all buildings several feet below the flood elevation and thus have very high levels of damage. Much more accurate flood loss estimates can be made at the district, campus or building-level. However, such estimates require more detailed data about individual buildings. Completing such detailed analysis is outside the domain of the Washington State K–12 Facilities Hazard Mitigation Plan, but it is within the domain for district hazard mitigation plans. The statewide planning effort provides the foundation to support more detailed district-specific mitigation planning efforts.
10.8 Flood Risk Assessments at the District, Campus, and Building Levels The previous sections of this chapter provided an overview of flood hazards and flood risk at the statewide level. As previously stated, more detailed district, campus, and building-level flood hazard and flood risk assessments require more detailed data on a building-by-building basis. Statewide assessments are meant for statewide planning purposes and are not accurate enough to be meaningful for a single district, campus or building without more detailed assessments.
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Detailed guidance for school districts to perform further flood hazard and flood risk assessments is provided in the Mitigation Planning Toolkit. The synopsis below outlines the main steps. The steps necessary for flood hazard and flood risk assessments vary depending on the flood source and on whether or not quantitative flood hazard data are available. However, for every case, the following basic information is needed:
A building’s number of stories, size, replacement value, and whether or not it has a basement.
Building and content replacement values.
Estimated displacement costs if a building has to be vacated for flood repairs to be made. Such estimates require evaluating where a district would relocate students if a building or buildings were rendered temporarily unusable because of flood damage.
Building first floor elevations. The simplest case, and the one that yields the most quantitative hazard and risk assessment, applies to campuses within FEMA-mapped floodplains and for which quantitative flood hazard data such as that shown previously in Table 10.2 is available. In this case, the main steps are:
Obtain campus-specific flood hazard data (see Table 10.2) from the FEMA Flood Insurance Study and FEMA Flood Insurance Rate Maps.
Use the FEMA depth-damage functions in the FEMA Benefit-Cost Analysis software to estimate building damages, content damages and displacement costs for each possible flood depth. These calculations are best done using a spreadsheet program such as Excel.
The most accurate measure of flood risk is the expected average annual loss total–the long term average, taking into account the probability and severity of all possible flood events. The expected average annual average loss can be calculated with the FEMA Benefit-Cost Software.
In this case, gathering a history of past flood events is useful to demonstrate the reality of flood risk but is not necessary for the quantitative flood hazard and risk calculations. The above steps are explained in more detail, with examples, in the Mitigation Planning Toolkit. For cases where quantitative flood hazard data are not available, fully quantitative flood hazard and risk assessments are not possible–the best assessments are semi-quantitative or qualitative. In this case, gathering a history of past flood events is the first step. One important caveat is that the absence of a history of past flood events may indicate that flood risk is low, but this is not necessarily the case. As discussed in Chapter Six, flood risk is inherently probabilistic. A campus that hasn’t had a flood in ten, 20 or 30 years may have just been “lucky” and flood damage might occur with floods of similar return periods. Or, the flood risk might have increased over time because of increasing development upstream in the
Page | 197 watershed (which increases runoff) or because of channel changes. Or, a campus might not have frequent flooding, but the level of damages for a 50-year or 100-year event might be very severe. Semi-quantitative or qualitative flood hazard and risk assessments can be based on several types of data or estimates including:
Documented history of past flood events. For campuses with a history of repetitive flooding, there may be enough events to make semi-quantitative estimates of the frequency/severity relationship for floods.
For flooding from non-FEMA mapped flood sources, including localized stormwater drainage flooding, engineers knowledgeable about local conditions may be able to make semi-quantitative estimates of the frequency/severity relationship for floods.
For sites subject to flooding from failures of dams, reservoirs or levees; engineers knowledgeable about local conditions and with knowledge of the structural characteristics and condition of the dams, reservoirs or levees may be able to make semi- quantitative estimates of the frequency/severity relationship for floods. In cases where there is some quantitative flood hazard data, such as the elevation of the 100-year flood only, a combination of the quantitative and semi-quantitative approaches is applicable. Purely qualitative flood hazard and risk assessments such as–the flood risk is high, medium or low–provides minimal information that is meaningful and should be avoided whenever possible.
10.9 Flood Mitigation Projects For K–12 facilities with substantial levels of flood risk, there are several types of potential flood mitigation measures available:
Replacement of a facility at high risk from floods with a new facility located outside of flood hazard zones.
Increasing the elevation of an existing building.
Minor flood-proofing actions that address the most vulnerable elements in a facility. Such projects include elevating at-grade utility infrastructure or relocating critical equipment or contents from basement levels of a building to higher levels.
Construction of levees, berms or flood walls to protect a facility.
Installation of flood gates including building water proofing measures.
Local drainage improvements where stormwater drainage is a problem. Replacing an at-risk facility with a new facility outside of flood hazards zones is essentially 100 percent effective in reducing future flood damages. A new replacement building also has other advantages such as energy efficiency and fully meeting current functionality requirements. Of course, the major impediment to widespread replacement is the cost.
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The extent to which any of the above mitigation measures are warranted depends on the level of flood risk and on district priorities. For K–12 facilities at high flood risk, FEMA grant funding is potentially available for any of the above types of flood mitigation measures. FEMA doesn’t replace existing facilities but does do acquisition/demolition projects in which the fair market value of a property is the total eligible project cost. FEMA-funded acquisition projects require demolition of the existing facility and deed restrictions to prevent future development of the area. Acceptable uses after demolition are limited to green space such as parks or sports fields with development limited to incidental structures such a restroom. With such projects the FEMA funding, which is typically 75 percent of the total project costs, can be used towards building a replacement facility. On a community or regional level, larger-scale flood control measures such as construction of upstream dams or detention basins and channel improvements may be effective in reducing flood risks. However, such larger-scale projects are outside the domain of responsibility for school districts.
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Chapter Eleven: Wildland/Urban Interface Fires
11.1 Overview Fire has posed a threat to mankind since the dawn of civilization. Fires often cause substantial damage to property and may also result in deaths and injuries. For the purposes of mitigation planning, we define three types of fires:
Structure fires and other localized fires.
Wildland fires.
Wildland/urban interface fires. Structure fires are fires where structures and contents are the primary fuel. In dealing with structure fires, fire departments typically have three primary objectives: 1) minimize casualties, 2) prevent a structure fire from spreading to other structures, and 3) minimize damage to the structure and contents. Structure fires and the other common types of fire, such as vehicle or trash fires, are most often limited to a single structure or location; although, in some cases they may spread to adjacent structures. Wildland fires are fires where vegetation (grass, brush, trees) is the primary fire fuel with few or no structures involved. For wildland fires, the most common suppression strategy is to contain the fire at its boundaries then let the fire burn itself out. Fire containment typically relies heavily on natural or manmade fire breaks. Water and chemical fire suppressants are used primarily to help make or defend a fire break rather than to put out an entire fire as would be the case with a structure fire. For wildland fires, fire suppression is generally a state and federal agency responsibility; although, local agencies may also participate. Fires in wilderness areas may also be allowed to burn out naturally for forest renewal and other environmental reasons. Wildland/urban interface fires are fires where the fire fuel includes both structures and vegetation. The defining characteristic of the wildland/urban interface area is that structures are built in, or immediately adjacent to, areas with essentially continuous vegetative fuel loads. When wildland fires occur in such areas, they often spread quickly to structures which may, unfortunately, become little more than additional fuel sources for wildland fires. Fire suppression efforts for wildland/urban interface fires focus first on savings lives and then on protecting structures to the greatest extent possible. Local fire agencies have primary fire suppression responsibility for most wildland/urban interface fires; although, state and federal agencies may also contribute. This chapter focuses on wildland/urban interface fires that pose a substantial threat to many parts of Washington and to districts with K–12 facilities in locations with significant risk from wildland/urban interface fires.
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Major fires in the urban/wildland interface have the potential for enormous destruction and high casualties. For example, the October, 1991 East Bay Fire in Oakland, California burned about 1,600 acres with 25 fatalities, 150 injuries, and over 3,300 single-family homes and 450 apartment units destroyed. Property damages were about $2.4 billion in 2013 dollars. This fire was fueled by high vegetative fuel loads and occurred on an unusually hot, dry, windy day. The fire spread extremely quickly with over 800 homes engulfed by fire within the first hour. The rapid spread of fire completely overwhelmed initial fire suppression efforts.
11.2 Wildland/Urban Interface Fires Many urban or suburban areas have a significant amount of landscaping and other vegetation. However, in most areas the fuel load of flammable vegetation is not continuous. It is broken by paved areas, open space, and areas of mowed grass with low fuel loads. In these areas, most fires are single structure fires. The combination of separation between buildings, fire breaks, and generally low total vegetative fuel loads make the risk of fire spreading much lower than in wildland areas. Furthermore, most developed areas in urban and suburban areas have water systems with good capacities to provide water for fire suppression and fire departments that respond quickly to fires, with sufficient personnel and apparatus to control fires effectively. Thus, the likelihood of a single structure fire spreading to involve multiple structures is generally quite low. Areas subject to wildland/urban interface fires have very different fire hazard characteristics that are more similar to those for wildland fires. The level of fire hazard for wildland/urban interface fires depends on:
Vegetative fuel load.
Topography.
Climate.
Ignition sources and frequency of fire ignitions.
Fire suppression resources (fire agency response time and resources of crews and apparatus, access and water supplies). High vegetative fuel loads, especially brush and trees, increase the level of wildland/urban fire hazard. Steep topography increases the level of fire risk by exacerbating fire spread and impeding fire suppression efforts by making access more difficult. The level of fire hazard in areas prone to wildland/urban interface fires is also substantially increased when weather conditions–including high temperatures, low humidity, and high winds– greatly accelerate the spread of wildland fires and make containment difficult or impossible. Fire suppression resources are typically much lower in wildland/urban interface fire areas than in more highly developed areas. Fire stations are more widely spaced with fewer resources of crews and apparatus and longer response times because of distance and/or limited access routes. Water resources for fire suppression are typically lower in these areas. They are often predominantly
Page | 201 residential and may be served by pumped pressure zones with limited water storage or by individual wells that provide no water for fire suppression. These reduced fire suppression resources make it more likely that a small wildland fire, or a single structure fire in an urban/wildland interface area, will spread before it can be extinguished. The level of risk from wildland/urban interface fires for K–12 facilities depends on:
Level of fire hazard as outlined above.
Value and importance of buildings and infrastructure.
Population at risk.
Availability of evacuation routes.
Vulnerability of the inventory at risk, including whether fire-safe construction practices and defensible space measures have been implemented. The level of risk from wildland/urban interface fire for K–12 facilities also depends on the characteristics of the community in which a facility is located. The risk is lower in communities with effective implementation of fire-safe construction practices and maintenance of defensible space. Conversely, the risk is higher in communities without fire-safe construction and maintenance of defensible space because there is a greater likelihood that a fire ignition will spread rapidly throughout the community and threaten a K–12 facility. Life safety risk in wildland/urban interface fires arises, in large part, from delays in evacuations once a fire has started. For K–12 facilities with significant risk from wildland/urban interface fires, a well-defined, practical and practiced evacuation plan is essential to minimize potential life safety risk.
11.3 Historical Fire Data for Washington State The 2013 Washington State Enhanced Mitigation Plan1 includes a list of significant wildland fires in Washington State since 1900. The largest fire, the 1902 Yacolt Fire in Skamania and Clark Counties, burned about 230,000 acres and resulted in 38 deaths. Since 1985, there have been 23 fires that burned more than 20,000 acres each destroying 439 homes and causing a total of seven deaths, including four firefighters. These fires also destroyed numerous outbuildings, damaged many more homes and also damaged infrastructure such as above ground utility lines. In addition, 36 structures were destroyed in 2000 at the U.S. Department of Energy’s Hanford site. This 192,000 acre fire was largely within the Hanford site. In July and August of 2014, the Carlton Complex Fire in Okanagan County burned over 250,000 acres and thus became the largest wildland fire in Washington history. The fire destroyed over 320 single family homes, more than 140 outbuildings, and several multi-family and commercial structures. No K–12 facilities were destroyed. However, the fire came within a few feet of the Pateros School (K–12), the only school in the Pateros School District.
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Figure 11.1 Pateros School Fire (July, 2014)
See, Washington State Wildland Fire Statistics2 for the most recent available ten-year period. Years 2001–2011 are shown in Figure 11.1 on the following page. Over this time period there was an average of 1,428 wildland fires per year with an average of 128,491 acres burned per year. These data are only for the federal and state agencies listed in Table 11.1 and do not include the mostly small wildland fires responded to by local fire agencies.
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Figure 11.2 Washington State Wildland Fire Statistics 2001-20112 Federal and State Agencies Only
Detailed data for the 2011 wildland fires, including ignition sources and acres burned, for fires within the jurisdictions of federal and state agencies are shown in Table 11.1. The data in Figure 11.1 and Table 11.1 do not include wildland fires responded to by local fire agencies. Detailed data for wildland fires responded to by local fire agencies in Washington are not available. National data compiled by the National Fire Protection Association3 indicate that local fire agencies respond to over 350,000 brush, grass, and forest fires every year. Of these fires, 41 percent were brush or brush and grass mixture fires, 37 percent were grass fires, ten percent were forest, woods, or wildland fires, and 12 percent were natural vegetation fires that were not classified further. Of these fires, only four percent burned over ten acres, 22 percent burned between one acre and ten acres, and 74 percent burned less than one acre. Nationwide, an average of about 4,800 buildings are damaged or destroyed by wildland or wildland/urban interface fires each year. Roughly similar statistics are likely to apply within Washington State. Given these national statistics, local fire agencies in Washington respond to many thousands of brush, grass, and forest fires every year. However, most of these fires are small and quickly extinguished. Fire ignitions in wildland areas, where the response is predominantly the responsibility of federal and state agencies are more likely to result in fires that burn large acreage.
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Table 11.1 2011 Washington Wildland Fire Data – Federal and State Agencies Only
Human Lightning Human Lightning Total Caused Caused Total Responsible Agency Caused Caused Acres Acres Acres Fires Fires Fire Burned Burned Burned Bureau of Indian Affairs 158 2,168 12 15 170 2,183
Bureau of Land Management 20 1,875 2 3 22 1,878
US Fish and Wildlife Service 4 87 0 0 4 87
National Park Service 17 5 0 0 17 5
US Forest Service 176 547 61 111 237 658 US Department of Defense 0 0 0 0 0 0 (Hanford Reservation) Washington DNR 504 7,538 37 14 541 7,552
Washington Fire Servicea 2 5,108 0 0 2 5,108
Statewide Totalsb 881 17,328 112 143 993 17,471
a Washington Fire Service is not defined in the source report. b Statewide totals shown are the sum of the entries. Reported totals in the source report differ slightly from the sum of the entries.
11.4 Wildland and Wildland/Urban Fire Hazard Mapping and Hazard Assessment The three maps on the following pages present different measures of wildland and wildland/urban interface fire hazards in Washington. Figure 11.2 shows Wildland/Interface Communities identified by the Washington State Department of Natural Resources. Figure 11.3 shows High Risk Wildland/Interface Communities and Statewide Assessment High and Moderate Risk Areas identified by the Washington State Department of Natural Resources. Figure 11.4 shows the United States Geological Survey Landfire Fire Return Periods. All of these maps must be interpreted carefully as discussed in Section 11.5.
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Figure 11.3 Wildland/Urban Interface Communities Identified by Washington Department of Natural Resources
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Figure 11.4 Washington Wildland/Urban Interface High Risk Communities and Statewide Assessment High and Moderate Risk Areas4
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Figure 11.55 United States Geological Survey Landfire Fire Return Period Map
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11.5 Wildland/Urban Interface Fire Hazard and Risk K–12 facilities that may have significant risk for wildland/urban interface fire are those within high hazard areas for wildland/urban interface fires as shown in the preceding maps and without adequate fire safe construction and defensible space. Table 11.2, on the following pages, identifies 236 K–12 facilities located within Wildland/Urban Interface Communities as identified by DNR. This table also includes the USGS fire return periods for these campuses and the corresponding probability of fire over a 50-year time period. Table 11.3 identifies an additional 418 K–12 facilities that are not within Wildland/Urban Interface Communities as identified by DNR but have USGS fire return periods less than 50 years. There are important caveats regarding the data/estimates in Tables 11.2 and 11.3. These caveats must be understood before making wildland/urban interface fire mitigation decisions for K–12 facilities within mapped fire hazard areas including:
The DNR rankings of Wildland/Urban Interface Communities have extreme, high, moderate or low risk and should be interpreted only as qualitative or semi-quantitative indicators of the relative level of risk. Facilities identified as being located in communities with “extreme” or “high” levels of risk may not have extreme or high risk as generally understood for mitigation planning purposes. Some of the extreme or high risk interface communities have long burn return periods per the USGS Landfire map.
The USGS Landfire Return Period values should also be interpreted as semi-quantitative indicators of the relative level of risk. The numerical estimates of the burn return period and the corresponding probabilities over a 50-year time period should not be interpreted literally. The DNR rankings and the USGS Landfire Return Periods are based on an analysis of fire regime characteristics–such as vegetative fuel loads, topography, climate, and fire suppression resources. The USGS Landfire Return Periods indicate higher levels of fire risk than suggested by historical fire data. The average annual acres burned (Table 11.1) suggest a statewide burn period of greater than 300 years. This is longer than the Landfire estimate of less than 50-years for most of Central and Eastern Washington with some locations have burn return periods of less than ten years. Furthermore, most of the acreage burned has been wildland containing relatively few structures and no K–12 facilities. This overlay of K–12 facilities, with mapped wildland/urban fire hazard areas, is only the first step in a risk assessment for wildland/urban interface fires. Additional facility data and analysis are needed to more accurately determine the potential risk to a specific school district and/or a specific campus. The ICOS Pre-Disaster Mitigation Database includes three key indicators of the level of wildland/urban interface fire risk for each campus: 1) identification of whether a campus is in a wildland/urban interface fire community as designated by the Washington Department of Natural Resources (DNR), 2) the DNR rating, and 3) the Landfire estimate of the burn return period.
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ICOS also has auto-generate report tables summarizing the campus-level hazard and risk for wildland/urban interface fires. The report tables include the three indicators listed above and also includes three district-provided inputs, identifying whether there are high fuel load areas near the campus, a history of wildland/urban interface fires near the campus, and whether fire agencies have expressed concern about wildland urban interface fires affecting the campus. These inputs are combined in ICOS to generate a preliminary hazard and risk level for each campus and a recommendation as to whether consultation with a local fire agency is encouraged. For campuses at high risk, building-level assessments by local fire agencies or other fire experts may be warranted. The Mitigation Planning Toolkit includes a template for districts to create summary reports tracking these evaluations, identifying buildings for which risk reduction measures are desired, and documenting the completion of these measures.
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Table 11.2 Wildland/Urban Interface Communities Identified by DNR
FACILITY INFORMATION WILDFIRE HAZARDS
USGS Landfire Fire Probability WUI Return within Community Facility Name District City Period Range 50 Year Time DNR Fire (Years) Perioda Hazard Rating
Concrete Elementary School Concrete Concrete Extreme N/A N/A Concrete High School Concrete Concrete Extreme N/A N/A Skagit River School House Concrete Concrete Extreme N/A N/A Special Services School Concrete Concrete Extreme N/A N/A Twin Cedars High School Concrete Concrete Extreme N/A N/A Cle Elum Roslyn High School Cle Elum-Roslyn Cle Elum Extreme 16-20 94.26% Glenwood Elementary School Glenwood Glenwood Extreme 16-20 94.26% Glenwood Secondary Glenwood Glenwood Extreme 16-20 94.26% Klickitat Elementary & High School Klickitat Klickitat Extreme 16-20 94.26% Lyle High School Lyle Lyle Extreme 16-20 94.26% Mary Walker High School Mary Walker Springdale Extreme 16-20 94.26% Parent Partner Program Mary Walker Springdale Extreme 16-20 94.26% Walter Strom Middle School Cle Elum-Roslyn Cle Elum Extreme 16-20 94.26% Centerville Elementary School Centerville Centerville Extreme 36-40 73.64% Pasadena Park Elementary School West Valley (Spokane) Spokane Extreme 36-40 73.64% Columbia High And Elementary School Columbia (Stevens) Hunters Extreme 51-60 60.05% Windsor Elementary School Cheney Spokane Extreme 61-70 53.94% Adna Elementary School Adna Chehalis Extreme 71-80 48.89% Cle Elum Roslyn Elementary School Cle Elum-Roslyn Cle Elum Extreme 71-80 48.89% Friday Harbor Elementary School San Juan Island Friday Harbor Extreme 71-80 48.89% Friday Harbor High School San Juan Island Friday Harbor Extreme 71-80 48.89% Friday Harbor Middle School San Juan Island Friday Harbor Extreme 71-80 48.89% Griffin Bay School San Juan Island Friday Harbor Extreme 71-80 48.89% Stuart Island Elementary School San Juan Island Friday Harbor Extreme 71-80 48.89% Swiftwater Learning Center Cle Elum-Roslyn Roslyn Extreme 71-80 48.89% Springdale Academy Mary Walker Springdale Extreme 81-90 44.66% Springdale Elementary School Mary Walker Springdale Extreme 81-90 44.66% Springdale Middle School Mary Walker Springdale Extreme 81-90 44.66% Great Northern Elementary School Great Northern Spokane Extreme 91-100 41.09% Ponderosa Elementary School Central Valley Spokane Extreme 201-300 18.16% Boston Harbor Elementary School Olympia Olympia Extreme 301-500 11.76% Crossroads Alternative High School Granite Falls Granite Falls Extreme 301-500 11.76% Granite Falls High School Granite Falls Granite Falls Extreme 301-500 11.76% Mountain Way Elementary School Granite Falls Granite Falls Extreme 301-500 11.76% Rochester Middle School Rochester Rochester Extreme 301-500 11.76% South Bay Elementary School North Thurston Lacey Extreme 301-500 11.76% Adna Middle High School Adna Chehalis Extreme 501-1000 6.45% Easton School Easton Easton Extreme 501-1000 6.45% Granite Falls Middle School Granite Falls Granite Falls Extreme 501-1000 6.45% Kendall Elementary School Mount Baker Maple Falls Extreme 501-1000 6.45% Beach Elementary Ferndale Lummi Island High N/A N/A Mount Erie Elementary School Anacortes Anacortes High N/A N/A Trafton Elementary School Arlington Arlington High N/A N/A Wayne M. Henkle Middle School White Salmon Valley White Salmon High 6-10 99.87% Beaver Valley School Cascade Leavenworth High 16-20 94.26% Columbia Technical High School White Salmon Valley White Salmon High 16-20 94.26% Home School Program (REACH) Methow Valley Winthrop High 16-20 94.26% Kettle Falls Elementary School Kettle Falls Kettle Falls High 16-20 94.26% Kettle Falls High School Kettle Falls Kettle Falls High 16-20 94.26% Loon Lake Elementary School Loon Lake Loon Lake High 16-20 94.26% Loon Lake Homelink Program Loon Lake Loon Lake High 16-20 94.26% Mead Preschool Mead Mead High 16-20 94.26% Meadow Ridge Elementary School Mead Mead High 16-20 94.26% Methow Valley Elementary School Methow Valley Winthrop High 16-20 94.26% Midway Elementary School Mead Colbert High 16-20 94.26% Nine Mile Falls Elementary School Nine Mile Falls Nine Mile Falls High 16-20 94.26% Northport Elementary School Northport Northport High 16-20 94.26% Northport High School Northport Northport High 16-20 94.26% Phoenix Alternative School Nine Mile Falls Nine Mile Falls High 16-20 94.26%
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Table 11.2–Continued Wildland/Urban Interface Communities Identified by DNR
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
Skyview Elementary School East Valley (Spokane) Spokane Valley High 16-20 94.26% Wellpinit-Fort Semco High School Wellpinit White Swan High 16-20 94.26% White Salmon Academy White Salmon Valley White Salmon High 16-20 94.26% Artz Fox Elementary School Mabton Mabton High 21-25 89.17% Camas Elementary School Wapato Wapato High 21-25 89.17% Chief Kamiakin Elementary School Sunnyside Sunnyside High 21-25 89.17% Compass High School Grandview Grandview High 21-25 89.17% Contract Learning Center Grandview Grandview High 21-25 89.17% Harrah Elementary School Mount Adams Harrah High 21-25 89.17% Mabton Middle School Mabton Mabton High 21-25 89.17% Mabton Senior High School Mabton Mabton High 21-25 89.17% McClure Elementary School Grandview Grandview High 21-25 89.17% Pace Alternative High School Wapato Wapato High 21-25 89.17% Pioneer Elementary School Sunnyside Sunnyside High 21-25 89.17% Satus Elementary School Wapato Wapato High 21-25 89.17% Wapato Middle School Wapato Wapato High 21-25 89.17% YVCC GED School Grandview Grandview High 21-25 89.17% Zillah Middle School Zillah Zillah High 21-25 89.17% Columbia High School White Salmon Valley White Salmon High 26-30 83.77% Manson Elementary School Manson Manson High 31-35 78.53% Manson Junior Senior High School Manson Manson High 31-35 78.53% Bickleton Elementary & High School Bickleton Bickleton High 36-40 73.64% Bickleton Elementary School Bickleton Bickleton High 36-40 73.64% East Valley Central Middle School East Valley (Yakima) Yakima High 36-40 73.64% East Valley Elementary School East Valley (Yakima) Yakima High 36-40 73.64% East Valley High School East Valley (Yakima) Yakima High 36-40 73.64% Holden Village Community School Lake Chelan Chelan High 36-40 73.64% Liberty Bell Junior Senior High School Methow Valley Winthrop High 36-40 73.64% Mead Senior High School Mead Spokane High 36-40 73.64% Mount Adams Middle School Mount Adams White Swan High 36-40 73.64% Moxee Elementary School East Valley (Yakima) Moxee High 36-40 73.64% Terrace Heights Elementary School East Valley (Yakima) Yakima High 36-40 73.64% White Swan High School Mount Adams White Swan High 36-40 73.64% Adams Elementary School Wapato Wapato High 51-60 60.05% Garfield Elementary School Toppenish Toppenish High 51-60 60.05% Grandview High School Grandview Grandview High 51-60 60.05% Grandview Middle School Grandview Grandview High 51-60 60.05% Granger Alternative High School Granger Granger High 51-60 60.05% Granger High School Granger Granger High 51-60 60.05% Granger Middle School Granger Granger High 51-60 60.05% Harrison Middle School Sunnyside Sunnyside High 51-60 60.05% Hilton Elementary School Zillah Zillah High 51-60 60.05% Kirkwood Elementary School Toppenish Toppenish High 51-60 60.05% Lincoln Elementary School Toppenish Toppenish High 51-60 60.05% Nine Mile Falls Office Nine Mile Falls Nine Mile Falls High 51-60 60.05% Outlook Elementary School Sunnyside Outlook High 51-60 60.05% Roosevelt Elementary School Granger Granger High 51-60 60.05% Sierra Vista Middle School Sunnyside Sunnyside High 51-60 60.05% Smith Elementary School Grandview Grandview High 51-60 60.05% Sun Valley Elementary School Sunnyside Sunnyside High 51-60 60.05% Sunnyside High School Sunnyside Sunnyside High 51-60 60.05% Sunnyside School District Office - Sunnyside Sunnyside High 51-60 60.05% Thompson Elementary School Grandview Grandview High 51-60 60.05% Toppenish High School Toppenish Toppenish High 51-60 60.05% Toppenish Middle School Toppenish Toppenish High 51-60 60.05% Toppenish Pre School Toppenish Toppenish High 51-60 60.05% Valley View Elementary School Toppenish Toppenish High 51-60 60.05% Wapato High School Wapato Wapato High 51-60 60.05% Washington Elementary School Sunnyside Sunnyside High 51-60 60.05% Zillah High School Zillah Zillah High 51-60 60.05%
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Table 11.2–Continued Wildland/Urban Interface Communities Identified by DNR
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
Zillah Intermediate School Zillah Zillah High 51-60 60.05% Chester Elementary School Central Valley Spokane High 61-70 53.94% East Valley High School East Valley (Spokane) Spokane Valley High 61-70 53.94% Mountain View Elementary School Shelton Shelton High 71-80 48.89% Olympic Middle School Shelton Shelton High 71-80 48.89% Pioneer Intermediate Middle School Pioneer Shelton High 71-80 48.89% Trout Lake Elementary School Trout Lake Trout Lake High 71-80 48.89% Trout Lake School Trout Lake Trout Lake High 71-80 48.89% Utsalady Elementary School Stanwood-Camano Camano Island High 71-80 48.89% Columbia Virtual Academy-Orient Orient Orient High 81-90 44.66% Orient Elementary School Orient Orient High 81-90 44.66% Farwell Elementary School Mead Spokane High 91-100 41.09%
Kettle Falls Bus Garage Kettle Falls Kettle Falls High 91-100 41.09%
Lake Spokane Elementary School Nine Mile Falls Nine Mile Falls High 91-100 41.09% Lakeside High School Nine Mile Falls Nine Mile Falls High 91-100 41.09% Lakeside Middle School Nine Mile Falls Nine Mile Falls High 91-100 41.09% Mead Alternative High School Mead Spokane High 91-100 41.09% Mountainside Middle School Mead Colbert High 91-100 41.09% Mt Spokane High School Mead Mead High 91-100 41.09% Northwood Middle School Mead Spokane High 91-100 41.09% Colbert Elementary School Mead Colbert High 201-300 18.16% Columbia Virtual Academy - Kettle Kettle Falls Kettle Falls High 201-300 18.16% Falls Kettle Falls Homelink Kettle Falls Kettle Falls High 201-300 18.16% Kettle Falls Middle School Kettle Falls Kettle Falls High 201-300 18.16% University High School Central Valley Spokane High 201-300 18.16%
Canyon Creek Middle School Washougal Washougal High 301-500 11.76%
Cape Horn Skye Elementary School Washougal Washougal High 301-500 11.76% Echo Glen School Issaquah Snoqualmie High 301-500 11.76% Fidalgo Elementary School Anacortes Anacortes High 301-500 11.76% Griffin School Griffin Olympia High 301-500 11.76% Index Elementary School Index Index High 301-500 11.76% Kalama Elem School Kalama Kalama High 301-500 11.76% Kalama Junior Senior High School Kalama Kalama High 301-500 11.76% Mary M Knight Elementary School Mary M. Knight Elma High 301-500 11.76% Mt. Solo Middle School Longview Longview High 301-500 11.76% Pioneer Primary School Pioneer Shelton High 301-500 11.76% Rose Valley Elementary School Kelso Kelso High 301-500 11.76% Southside Elementary School Southside Shelton High 301-500 11.76% Twin Falls Middle School Snoqualmie Valley North Bend High 301-500 11.76%
Woodland High School Woodland Woodland High 301-500 11.76% Yacolt Primary School Battle Ground Yacolt High 301-500 11.76% Carrolls Elementary School Kelso Kelso High 501-1000 6.45% Clear Lake Elementary School Sedro-Woolley Clear Lake High 501-1000 6.45% Coweeman Middle School Kelso Kelso High 501-1000 6.45% Elger Bay Elementary School Stanwood-Camano Camano Island High 501-1000 6.45% Hood Canal Elementary & Junior High Hood Canal Shelton High 501-1000 6.45% School Kelso High School Kelso Kelso High 501-1000 6.45% Loowit High School Kelso Kelso High 501-1000 6.45%
Ocosta Elementary School Ocosta Westport High 501-1000 6.45%
Ocosta Junior Senior High School Ocosta Westport High 501-1000 6.45%
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Table 11.2–Continued Wildland/Urban Interface Communities Identified by DNR
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
Skykomish Elementary School Skykomish Skykomish High 501-1000 6.45% Skykomish High School Skykomish Skykomish High 501-1000 6.45% Toutle Lake Elementary School Toutle Lake Toutle High 501-1000 6.45% Toutle Lake High School Toutle Lake Toutle High 501-1000 6.45% Breidablik Elementary School North Kitsap Poulsbo Moderate N/A N/A Burley Glenwood Elementary School South Kitsap Port Orchard Moderate N/A N/A Bainbridge Commodore Center Bainbridge Island Moderate N/A N/A Island David Wolfle Elementary School North Kitsap Kingston Moderate N/A N/A
Hilder Pearson Elementary School North Kitsap Poulsbo Moderate N/A N/A
Kingston High School North Kitsap Kingston Moderate N/A N/A North Kitsap Community Center North Kitsap Poulsbo Moderate N/A N/A North Kitsap High School North Kitsap Poulsbo Moderate N/A N/A OASIS School K-12 Orcas Island Eastsound Moderate N/A N/A Orcas Island Elementary School Orcas Island Eastsound Moderate N/A N/A Pal Program North Kitsap Poulsbo Moderate N/A N/A Poulsbo Elementary School North Kitsap Poulsbo Moderate N/A N/A Poulsbo Middle School North Kitsap Poulsbo Moderate N/A N/A Silverdale Elementary School Central Kitsap Silverdale Moderate N/A N/A South Colby Elementary School South Kitsap Port Orchard Moderate N/A N/A
Vinland Elementary School North Kitsap Poulsbo Moderate N/A N/A
Kittitas High School Kittitas Kittitas Moderate 36-40 73.64%
Kittitas B-5 Special Education Program Kittitas Kittitas Moderate 61-70 53.94%
Kittitas Elementary School Kittitas Kittitas Moderate 61-70 53.94% Bainbridge Bainbridge Special Education Services Bainbridge Island Moderate 71-80 48.89% Island Bayview Alternative School South Whidbey Langley Moderate 71-80 48.89% Coupeville Middle School Coupeville Coupeville Moderate 71-80 48.89% Hillcrest Elementary School Oak Harbor Oak Harbor Moderate 71-80 48.89% John Sedgwick Junior High School South Kitsap Port Orchard Moderate 71-80 48.89% Klahowya Secondary School Central Kitsap Silverdale Moderate 71-80 48.89% Langley Middle School South Whidbey Langley Moderate 71-80 48.89% Mullenix Ridge Elementary School South Kitsap Port Orchard Moderate 71-80 48.89% North Whidbey Middle School Oak Harbor Oak Harbor Moderate 71-80 48.89% Oak Harbor Elementary School Oak Harbor Oak Harbor Moderate 71-80 48.89% Oak Harbor High School Oak Harbor Oak Harbor Moderate 71-80 48.89% Olalla Elementary School South Kitsap Port Orchard Moderate 71-80 48.89% Olympic View Elementary Oak Harbor Oak Harbor Moderate 71-80 48.89% Orcas Island High School Orcas Island Eastsound Moderate 71-80 48.89% Orcas Island Middle School Orcas Island Eastsound Moderate 71-80 48.89% Bainbridge Ordway Elementary School Bainbridge Island Moderate 71-80 48.89% Island Sidney Glen Elementary School South Kitsap Port Orchard Moderate 71-80 48.89% South Whidbey Elementary School South Whidbey Langley Moderate 71-80 48.89% South Whidbey High School South Whidbey Langley Moderate 71-80 48.89% South Whidbey Special Services South Whidbey Langley Moderate 71-80 48.89% Whidbey Island Academy Shared South Whidbey Langley Moderate 71-80 48.89% School Captain Charles Wilkes Elementary Bainbridge Bainbridge Island Moderate 301-500 11.76% School Island Green Mountain Elementary School Central Kitsap Bremerton Moderate 301-500 11.76% Kingston Middle School North Kitsap Kingston Moderate 301-500 11.76% Special Programs North Kitsap Poulsbo Moderate 301-500 11.76% Broadview Elementary School Oak Harbor Oak Harbor Moderate 501-1000 6.45% Cedar Program Coupeville Coupeville Moderate 501-1000 6.45% Coupeville Elementary School Coupeville Coupeville Moderate 501-1000 6.45% Coupeville High School Coupeville Coupeville Moderate 501-1000 6.45% Crescent Harbor Elementary Oak Harbor Oak Harbor Moderate 501-1000 6.45%
Page | 214
Table 11.2–Continued Wildland/Urban Interface Communities Identified by DNR
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
HomeConnection Oak Harbor Oak Harbor Moderate 501-1000 6.45%
Middle School Options North Kitsap Kingston Moderate 501-1000 6.45%
Oak Harbor Aadministrative Service Oak Harbor Oak Harbor Moderate 501-1000 6.45% Center Oak Harbor Middle School Oak Harbor Oak Harbor Moderate 501-1000 6.45% Special Education Oak Harbor Oak Harbor Moderate 501-1000 6.45% Lopez Middle High School Lopez Island Lopez Island Low N/A N/A Cape Flattery Preschool Cape Flattery Sekiu Low 501-1000 6.45% Decatur Elementary School Lopez Island Anacortes Low 501-1000 6.45% Lopez Elementary School Lopez Island Lopez Island Low 501-1000 6.45% Neah Bay Elementary School Cape Flattery Neah Bay Low 501-1000 6.45% Neah Bay Junior Senior High School Cape Flattery Neah Bay Low 501-1000 6.45% Shaw Island Elementary School Shaw Island Shaw Island Low 501-1000 6.45% Waldron Island School Orcas Island Waldron Island Low 501-1000 6.45% aLandfire Return Periods/Probabilities should not be interpreted literally, but rather as a measure of relative fire hazard level. See discussion in subsection 11.5.
Page | 215
Table 11.3 USGS Landfire Return Periods Less Than 50 Years K–12 Facilities Not Within DNR Wildland/Urban Interface Communities
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
Benjamin Franklin Elementary School Vancouver Vancouver N/A 6-10 99.87% Bethel Online Academy Bethel Spanaway N/A 41435 99.87%
Black Lake Elementary School Tumwater Olympia N/A 6-10 99.87%
Carson Elementary School Puyallup Puyallup N/A 6-10 99.87% Covington Middle School Evergreen (Clark) Vancouver N/A 6-10 99.87% Early Childhood Education Center Vancouver Vancouver N/A 6-10 99.87% Edmonds Heights K-12 School Edmonds Edmonds N/A 6-10 99.87% Ellsworth Elementary School Evergreen (Clark) Vancouver N/A 6-10 99.87% Endeavour Elementary School Evergreen (Clark) Vancouver N/A 6-10 99.87% Fairview Junior High School Central Kitsap Bremerton N/A 6-10 99.87% Fir Grove Childrens Center Vancouver Vancouver N/A 6-10 99.87% Fort Vancouver High School Vancouver Vancouver N/A 6-10 99.87% Franklin Elementary School Lake Washington Kirkland N/A 6-10 99.87% George C. Marshall Elementary School Vancouver Vancouver N/A 6-10 99.87% Gov. John Rogers High School Puyallup Puyallup N/A 6-10 99.87% Harry S. Truman Elementary School Vancouver Vancouver N/A 6-10 99.87% Health and Bioscience Academy Evergreen (Clark) Vancouver N/A 6-10 99.87% Hough Elementary School Vancouver Vancouver N/A 6-10 99.87% Hudson's Bay High School Vancouver Vancouver N/A 6-10 99.87% Image Elementary School Evergreen (Clark) Vancouver N/A 6-10 99.87% Kent Mountain View Academy Kent Des Moines N/A 6-10 99.87% Lake Dolloff Elementary School Federal Way Auburn N/A 6-10 99.87% Lewis and Clark High School Vancouver Vancouver N/A 6-10 99.87% Lochburn Middle School Clover Park Lakewood N/A 6-10 99.87% Marrion Elementary School Evergreen (Clark) Vancouver N/A 6-10 99.87% Martin Luther King Elementary School Vancouver Vancouver N/A 6-10 99.87% McLoughlin Middle School Vancouver Vancouver N/A 6-10 99.87% Mountain Meadow Elementary School White River Buckley N/A 6-10 99.87% Naches Trail Elementary School Bethel Tacoma N/A 6-10 99.87% New Market High School Tumwater Tumwater N/A 6-10 99.87% Nierenberg Center Vancouver Vancouver N/A 6-10 99.87% Orchards Elementary School Evergreen (Clark) Vancouver N/A 6-10 99.87% Pioneer Valley Preschool Bethel Spanaway N/A 6-10 99.87% Ridgefield High School Ridgefield Ridgefield N/A 6-10 99.87% Riverview Elementary School Evergreen (Clark) Vancouver N/A 6-10 99.87% Roosevelt Elementary School Vancouver Vancouver N/A 6-10 99.87% Silver Star Elementary School Evergreen (Clark) Vancouver N/A 6-10 99.87% Sorenson Early Childhood Center Northshore Bothell N/A 6-10 99.87% Spanaway Elementary School/ Bethel Spanaway N/A 6-10 99.87% ECEAP/Preschool Spanaway Junior High School Bethel Tacoma N/A 6-10 99.87% Spanaway Lake High School/Preschool Bethel Spanaway N/A 6-10 99.87% Thompson Preschool Bethel Tacoma N/A 6-10 99.87% Union Ridge Elementary School Ridgefield Ridgefield N/A 6-10 99.87% Vancouver School of Arts and Vancouver Vancouver N/A 6-10 99.87% Academics Walnut Grove Elementary School Vancouver Vancouver N/A 6-10 99.87% Arcadia Elementary School Deer Park Deer Park N/A 16-20 94.26% Aster Elementary School Colville Coleville N/A 16-20 94.26% Bemiss Elementary School Spokane Spokane N/A 16-20 94.26% Bowdish Middle School Central Valley Spokane N/A 16-20 94.26% Cascade High School Cascade Leavenworth N/A 16-20 94.26% Cashmere High School Cashmere Cashmere N/A 16-20 94.26% Cashmere Middle School Cashmere Cashmere N/A 16-20 94.26% Central Valley High School Central Valley Veradale N/A 16-20 94.26% Central Valley Kindergarten Center Central Valley Spokane Valley N/A 16-20 94.26% Chattaroy Elementary School Riverside Chattaroy N/A 16-20 94.26% Chewelah Alternative Chewelah Chewelah N/A 16-20 94.26%
Page | 216
Table 11.3–Continued USGS Landfire Return Periods Less Than 50 Years K–12 Facilities Not Within DNR Wildland/Urban Interface Communities
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
Columbia Virtual Academy Valley Valley N/A 16-20 94.26%
Columbia Virtual Academy-Colville Colville Colville N/A 16-20 94.26% Creston Elementary School Creston Creston N/A 16-20 94.26% Creston Junior Senior High School Creston Creston N/A 16-20 94.26% Curlew Elementary & High School Curlew Curlew N/A 16-20 94.26% Davenport Elementary School Davenport Davenport N/A 16-20 94.26% Deer Park Elementary School Deer Park Deer Park N/A 16-20 94.26% Deer Park High School Deer Park Deer Park N/A 16-20 94.26% Deer Park Home Link Program Deer Park Deer Park N/A 16-20 94.26% Deer Park Middle School Deer Park Deer Park N/A 16-20 94.26% East Farms Elementary School East Valley (Spokane) Newman Lake N/A 16-20 94.26% Evergreen Elementary School Mead Spokane N/A 16-20 94.26% Evergreen School Evergreen (Stevens) Gifford N/A 16-20 94.26% Fort Colville Elementary School Colville Colville N/A 16-20 94.26% Franklin Elementary School Pullman Pullman N/A 16-20 94.26% Freeman High School Freeman Rockford N/A 16-20 94.26% Garfield at Palouse High School Garfield Palouse N/A 16-20 94.26% Garfield Elementary School Garfield Garfield N/A 16-20 94.26% Garfield Middle School Garfield Garfield N/A 16-20 94.26% Gess Elementary School Chewelah Chewelah N/A 16-20 94.26% Greenacres Elementary School Central Valley Greenacres N/A 16-20 94.26% Hofstetter Elementary School Colville Colville N/A 16-20 94.26% Home Link Alternative Chewelah Chewelah N/A 16-20 94.26% Icicle River Middle School Cascade Leavenworth N/A 16-20 94.26% Jefferson Elementary School Pullman Pullman N/A 16-20 94.26% Jenkins Middle School Chewelah Chewelah N/A 16-20 94.26% Jenkins Senior High School Chewelah Chewelah N/A 16-20 94.26% Lamont Middle School Lamont Lamont N/A 16-20 94.26% Liberty Junior High & Elementary Liberty Spangle N/A 16-20 94.26% School Liberty Lake Elementary School Central Valley Liberty Lake N/A 16-20 94.26% Longfellow Elementary School Spokane Spokane N/A 16-20 94.26% Madison Elementary School Spokane Spokane N/A 16-20 94.26% Mead Support Services Mead Mead N/A 16-20 94.26% Moran Prairie Elementary School Spokane Spokane N/A 16-20 94.26% Mountain View Middle School East Valley (Spokane) Newman Lake N/A 16-20 94.26% Newport Alternative High School Newport Newport N/A 16-20 94.26% Newport High School Newport Newport N/A 16-20 94.26% Newport Parent Partnership Newport Newport N/A 16-20 94.26% Oakesdale High School Oakesdale Oakesdale N/A 16-20 94.26% Off-Campus Special Education Central Valley Spokane Valley N/A 16-20 94.26% Orchard Prairie Elementary School Orchard Prairie Spokane N/A 16-20 94.26% Osborn Elementary School Cascade Leavenworth N/A 16-20 94.26% Palouse at Garfield Middle School Palouse Palouse N/A 16-20 94.26% Palouse Elementary School Palouse Palouse N/A 16-20 94.26% Palouse High School Palouse Palouse N/A 16-20 94.26% Panorama Distance Colville Colville N/A 16-20 94.26% Panorama School Colville Colville N/A 16-20 94.26% Pullman High School Pullman Pullman N/A 16-20 94.26% Republic Senior High School Republic Republic N/A 16-20 94.26%
Riverside Elementary School Riverside Chattaroy N/A 16-20 94.26%
Riverside High School Riverside Chattaroy, N/A 16-20 94.26%
Riverside Middle School Riverside Chattaroy N/A 16-20 94.26% Rogers High School Spokane Spokane N/A 16-20 94.26% Sadie Halstead Middle School Newport Newport N/A 16-20 94.26% Selkirk Elementary School Selkirk Metaline Falls N/A 16-20 94.26%
Page | 217
Table 11.3–Continued USGS Landfire Return Periods Less Than 50 Years K–12 Facilities Not Within DNR Wildland/Urban Interface Communities
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
Selkirk High School Selkirk Ione N/A 16-20 94.26% Selkirk Junior Senior High School Selkirk Ione N/A 16-20 94.26% Selkirk Middle School Selkirk Ione N/A 16-20 94.26% Shadle Park High School Spokane Spokane N/A 16-20 94.26% Shiloh Hills Elementary School Mead Spokane N/A 16-20 94.26% Stratton Elementary School Newport Newport N/A 16-20 94.26% Summit Valley School Summit Valley Addy N/A 16-20 94.26% Sunrise Elementary School Central Valley Veradale N/A 16-20 94.26% Tekoa Elementary School Tekoa Tekoa N/A 16-20 94.26% Tekoa High School Tekoa Tekoa N/A 16-20 94.26% Valley School Valley Valley N/A 16-20 94.26% Wellpinit Alliance High School Wellpinit Wellpinit N/A 16-20 94.26% Westview Elementary School Spokane Spokane N/A 16-20 94.26% Willard Elementary School Spokane Spokane N/A 16-20 94.26% Wilson Elementary School Spokane Spokane N/A 16-20 94.26% Woodridge Elementary School Spokane Spokane N/A 16-20 94.26% ALPS Alternative Learning Placement Othello Othello N/A 21-25 89.17% Site Amistad Elementary School Kennewick Kennewick N/A 21-25 89.17% Badger Mountain Elementary School Richland Richland N/A 21-25 89.17% Bridgeport Aurora High School Bridgeport Bridgeport N/A 21-25 89.17% Canyon View Elementary School Kennewick Kennewick N/A 21-25 89.17% Captain Gray Elementary/ Early Pasco Pasco N/A 21-25 89.17% Learning Center Carmichael Middle School Richland Richland N/A 21-25 89.17% Chiawana High School Pasco Pasco N/A 21-25 89.17% Chief Joseph Middle School Richland Richland N/A 21-25 89.17% Chief Moses Middle School Moses Lake Moses Lake N/A 21-25 89.17% Colton School Colton Colton N/A 21-25 89.17% Columbia Columbia Elementary School Burbank N/A 21-25 89.17% (Walla Walla) Columbia Columbia High School Burbank N/A 21-25 89.17% (Walla Walla)
Cottonwood Elementary School Kennewick N/A 21-25 89.17%
Dallesport Elementary School Lyle Dallesport N/A 21-25 89.17% Delta High School Richland N/A 21-25 89.17% Developmental Preschool Wahluke Mattawa N/A 21-25 89.17% Eastgate Elementary School Kennewick Kennewick N/A 21-25 89.17% Edison Elementary School Kennewick Kennewick N/A 21-25 89.17% Ellen Ochoa Middle School Pasco Pasco N/A 21-25 89.17% Emerson Elementary School Pasco Pasco N/A 21-25 89.17% Enterprise Middle School Richland West Richland N/A 21-25 89.17% Entiat Middle and High School Entiat Entiat N/A 21-25 89.17% Finley Elementary School Finley Kennewick N/A 21-25 89.17% Finley Middle School Finley Kennewick N/A 21-25 89.17% Garden Heights Elementary School Moses Lake Moses Lake N/A 21-25 89.17% Grainger Elementary School Okanogan Okanogan N/A 21-25 89.17% Hanford High School Richland Richland N/A 21-25 89.17%
Hawthorne Elementary School Kennewick Kennewick N/A 21-25 89.17%
Highlands Middle School Kennewick Kennewick N/A 21-25 89.17% James McGee Elementary School Pasco Pasco N/A 21-25 89.17% Jefferson Elementary School Richland Richland N/A 21-25 89.17% Kamiakin High School Kennewick Kennewick N/A 21-25 89.17% Keene-Riverview Elementary School Prosser Prosser N/A 21-25 89.17% Keewaydin Discovery Center Kennewick Kennewick N/A 21-25 89.17% Kennewick Administrative Office Kennewick Kennewick N/A 21-25 89.17% Kennewick High School Kennewick Kennewick N/A 21-25 89.17% Kiona-Benton City High School Kiona-Benton City Benton City N/A 21-25 89.17% Kiona-Benton Intermediate Kiona-Benton City Benton City N/A 21-25 89.17% Page | 218
Table 11.3–Continued USGS Landfire Return Periods Less Than 50 Years K–12 Facilities Not Within DNR Wildland/Urban Interface Communities
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
Legacy High School Kennewick Kennewick N/A 21-25 89.17% Lewis & Clark Elementary School Richland Richland N/A 21-25 89.17% Lewis & Clark Middle School Yakima Yakima N/A 21-25 89.17% Longfellow Elementary School Pasco Pasco N/A 21-25 89.17% Longview Elementary School Moses Lake Moses Lake N/A 21-25 89.17% Marcus Whitman Elementary School Richland Richland N/A 21-25 89.17% Mark Twain Elementary School Pasco Pasco N/A 21-25 89.17% Mattawa Elementary Preschool Wahluke Mattawa N/A 21-25 89.17% Mattawa Elementary School Wahluke Mattawa N/A 21-25 89.17% Maya Angelou Elementary School Pasco Pasco N/A 21-25 89.17% McLoughlin Middle School Pasco Pasco N/A 21-25 89.17% Mesa Elementary School North Franklin Mesa N/A 21-25 89.17% Mid-Columbia Parent Partnership Kennewick Kennewick N/A 21-25 89.17% Morris Schott Elementary School Wahluke Mattawa N/A 21-25 89.17% Moses Lake High School Moses Lake Moses Lake N/A 21-25 89.17% N Omak Elementary School Omak Omak N/A 21-25 89.17% New Horizons High School Pasco Pasco N/A 21-25 89.17% Okanogan Alternative High School Okanogan Okanogan N/A 21-25 89.17% Okanogan Middle School Okanogan Okanogan N/A 21-25 89.17% Okanogan Outreach Alternative Okanogan Omak N/A 21-25 89.17% School Omak Alternative High School Omak Omak N/A 21-25 89.17% Omak High School Omak Omak N/A 21-25 89.17% Omak Middle School Omak Omak N/A 21-25 89.17% Palisades Elementary School Palisades Palisades N/A 21-25 89.17% Park Middle School Kennewick Kennewick N/A 21-25 89.17% Pasco Early Childhood Pasco Pasco N/A 21-25 89.17% Pasco Senior High School Pasco Pasco N/A 21-25 89.17% Pateros Elementary School Pateros Pateros N/A 21-25 89.17% Pateros High School Pateros Pateros N/A 21-25 89.17% Paterson Elementary School Paterson Paterson N/A 21-25 89.17% Paul Rumburg Elementary School Entiat Entiat N/A 21-25 89.17% Phoenix High School Kennewick Kennewick N/A 21-25 89.17% Prosser Falls Education Center Prosser Prosser N/A 21-25 89.17% Richland High School Richland Richland N/A 21-25 89.17% River View High School Finley Kennewick N/A 21-25 89.17% Rivers Edge High School Richland Richland N/A 21-25 89.17% Robert Frost Elementary School Pasco Pasco N/A 21-25 89.17% Rock Island Elementary School Eastmont Rock Island N/A 21-25 89.17% Rowena Chess Elementary School Pasco Pasco N/A 21-25 89.17% Ruth Livingston Elementary School Pasco Pasco N/A 21-25 89.17% Sacajawea Elementary School Richland Richland N/A 21-25 89.17% Saddle Mountain Elementary School Wahluke Mattawa N/A 21-25 89.17% Sentinel Technical Alternative School Wahluke Mattawa N/A 21-25 89.17% Special Programs Richland Richland N/A 21-25 89.17% Stanton Alternative School Yakima Yakima N/A 21-25 89.17% Stevens Middle School Pasco Pasco N/A 21-25 89.17% Sunnyside Elementary School Pullman Pullman N/A 21-25 89.17% Sunset View Elementary School Kennewick Kennewick N/A 21-25 89.17% Tapteal Elementary School Richland West Richland N/A 21-25 89.17% Three Rivers Home Link Richland Richland N/A 21-25 89.17% Tonasket Elementary School Tonasket Tonasket N/A 21-25 89.17% Tonasket High School Tonasket Tonasket N/A 21-25 89.17% Tonasket Middle School Tonasket Tonasket N/A 21-25 89.17% Transportation Maintenance Center Yakima Yakima N/A 21-25 89.17% Tri-Tech Skills Center Kennewick Kennewick N/A 21-25 89.17% Twin Rivers Group Home Richland Richland N/A 21-25 89.17%
Page | 219
Table 11.3–Continued USGS Landfire Return Periods Less Than 50 Years K-12 Facilities Not Within DNR Wildland/Urban Interface Communities
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
Virgie Robinson Elementary School Pasco Pasco N/A 21-25 89.17% Vista Elementary School Kennewick Kennewick N/A 21-25 89.17% Wahluke High School Wahluke Mattawa N/A 21-25 89.17% Wahluke Junior High School Wahluke Mattawa N/A 21-25 89.17% Washington Elementary School Kennewick Kennewick N/A 21-25 89.17% Washington Virtual Academy Omak Omak Omak N/A 21-25 89.17% Elem./M.S./H.S. Westgate Elementary School Kennewick Kennewick N/A 21-25 89.17% Whittier Elementary School Pasco Pasco N/A 21-25 89.17% Wiley Elementary School Richland West Richland N/A 21-25 89.17% Wilson Creek Elementary School Wilson Creek Wilson Creek N/A 21-25 89.17% Wilson Creek High School Wilson Creek Wilson Creek N/A 21-25 89.17% Hulan L. Whitson Elementary School White Salmon Valley White Salmon N/A 26-30 83.77% Collins Alternative Programs White River Buckley N/A 31-35 78.53% Daffodil Valley Elementary School Sumner Sumner N/A 31-35 78.53% Roosevelt Elementary School Roosevelt Roosevelt N/A 31-35 78.53% Abraham Lincoln Elementary School Wenatchee Wenatchee N/A 36-40 73.64% Ahtanum Valley Elementary School West Valley (Yakima) Yakima N/A 36-40 73.64% Almira Coulee Hartline High School Coulee-Hartline Coulee City N/A 36-40 73.64% Almira Elementary School Almira Almira N/A 36-40 73.64% Apple Valley Elementary School West Valley (Yakima) Yakima N/A 36-40 73.64% Asotin Elementary School Asotin-Anatone Asotin N/A 36-40 73.64% Asotin Junior Senior High School Asotin-Anatone Asotin N/A 36-40 73.64% Benge Elementary School Benge Benge N/A 36-40 73.64% Berney Elementary School Walla Walla Walla Walla N/A 36-40 73.64% Brentwood Elementary School Mead Spokane N/A 36-40 73.64% Brewster Bus Garage Brewster Brewster N/A 36-40 73.64% Brewster Elementary School Brewster Brewster N/A 36-40 73.64% Brewster High School Brewster Brewster N/A 36-40 73.64% Brewster Junior High School Brewster Brewster N/A 36-40 73.64% Bridgeport Elementary School Bridgeport Bridgeport N/A 36-40 73.64% Bridgeport High School Bridgeport Bridgeport N/A 36-40 73.64% Bridgeport Middle School Bridgeport Bridgeport N/A 36-40 73.64% Broadway Elementary School Central Valley Spokane N/A 36-40 73.64% Cascade Elementary School Eastmont East Wenatchee N/A 36-40 73.64% Centennial Middle School West Valley (Spokane) Spokane N/A 36-40 73.64% Center Elementary School Grand Coulee Dam Grand Coulee N/A 36-40 73.64% Charles Francis Adams High School Clarkston Clarkston N/A 36-40 73.64% Chelan High School Lake Chelan Chelan N/A 36-40 73.64% Chelan Middle School Lake Chelan Chelan N/A 36-40 73.64% Chelan Prepatory High School Lake Chelan Chelan N/A 36-40 73.64% Clarkston School District Technology Clarkston Clarkston N/A 36-40 73.64% Building Clovis Point Intermediate School Eastmont East Wenatchee N/A 36-40 73.64% Colfax High School Colfax Colfax N/A 36-40 73.64% Columbia Elementary School Wenatchee Wenatchee N/A 36-40 73.64% Cooper Elementary School Spokane Spokane N/A 36-40 73.64% Cottonwood Elementary School West Valley (Yakima) Yakima N/A 36-40 73.64% Coulee City Elementary School Coulee-Hartline Coulee City N/A 36-40 73.64% Coulee City Middle School Coulee-Hartline Coulee City N/A 36-40 73.64% Damman Elementary School Damman Ellensburg N/A 36-40 73.64% Davenport Senior High School Davenport Davenport N/A 36-40 73.64% Davis Elementary School College Place College Place N/A 36-40 73.64% Davis High School Yakima Yakima N/A 36-40 73.64% Dixie Elementary School Dixie Dixie N/A 36-40 73.64% E Omak Elementary School Omak Omak N/A 36-40 73.64% Eastmont Columbia Virtual Academy Eastmont East Wenatchee N/A 36-40 73.64%
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Table 11.3–Continued USGS Landfire Return Periods Less Than 50 Years K–12 Facilities Not Within DNR Wildland/Urban Interface Communities
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
Eastmont Junior High School Eastmont East Wenatchee N/A 36-40 73.64%
Eastmont Senior High School Eastmont East Wenatchee N/A 36-40 73.64%
Edison Elementary School Walla Walla Walla Walla N/A 36-40 73.64% Educational Opportunity Center Clarkston Clarkston N/A 36-40 73.64% Elementary Alternative Center Clarkston Clarkston N/A 36-40 73.64% Ellensburg High School Ellensburg Ellensburg N/A 36-40 73.64% Endicott-St John Elementary and Endicott Endicott N/A 36-40 73.64% Middle Foothills Middle School Wenatchee Wenatchee N/A 36-40 73.64% Franklin Middle School Yakima Yakima N/A 36-40 73.64% Freeman Elementary School Freeman Rockford N/A 36-40 73.64% Freeman Middle School Freeman Rockford N/A 36-40 73.64% Gilbert Elementary School Yakima Yakima N/A 36-40 73.64% Glacier Valley High School Lake Chelan Chelan N/A 36-40 73.64% Glover Middle School Spokane Spokane N/A 36-40 73.64% Goldendale High School Goldendale Goldendale N/A 36-40 73.64% Goldendale Middle School Goldendale Goldendale N/A 36-40 73.64% Goldendale Primary School Goldendale Goldendale N/A 36-40 73.64% Goldendale Support Service Center Goldendale Goldendale N/A 36-40 73.64% Grand Coulee Dam Middle School Grand Coulee Dam Grand Coulee N/A 36-40 73.64% Grant Elementary School Eastmont East Wenatchee N/A 36-40 73.64%
Grantham Elementary School Clarkston Clarkston N/A 36-40 73.64% Green Park Elementary School Walla Walla Walla Walla N/A 36-40 73.64% Harrington Elementary School Harrington Harrington N/A 36-40 73.64% Harrington High School Harrington Harrington N/A 36-40 73.64% Heights Elementary School Clarkston Clarkston N/A 36-40 73.64% Highland Elementary School Clarkston Clarkston N/A 36-40 73.64% Highland High School Highland Cowiche N/A 36-40 73.64% Highland Junior High School Highland Cowiche N/A 36-40 73.64% Homelink Walla Walla Walla Walla N/A 36-40 73.64% Independent Learning Center Methow Valley Twisp N/A 36-40 73.64% John Campbell Elementary School Selah Selah N/A 36-40 73.64% John Newbery Elementary School Wenatchee Wenatchee N/A 36-40 73.64% K-12 Ellensburg Learning Center Ellensburg Ellensburg N/A 36-40 73.64% Kahlotus Elementary & High School Kahlotus Kahlotus N/A 36-40 73.64% Keller Elementary School Keller Keller N/A 36-40 73.64%
Kenroy Elementary School Eastmont East Wenatchee N/A 36-40 73.64%
Lacrosse Elementary School LaCrosse Lacrosse N/A 36-40 73.64% Lacrosse High School LaCrosse Lacrosse N/A 36-40 73.64% Lake Chelan Preschool Lake Chelan Chelan N/A 36-40 73.64% Leonard M Jennings Elementary Colfax Colfax N/A 36-40 73.64% School Lewis and Clark Elementary School Wenatchee Wenatchee N/A 36-40 73.64% Libby Center Spokane Spokane N/A 36-40 73.64% Lincoln Elementary School Ellensburg Ellensburg N/A 36-40 73.64% Lincoln Middle School Clarkston Clarkston N/A 36-40 73.64% Lincoln Middle School Pullman Pullman N/A 36-40 73.64% Logan Elementary School Spokane Spokane N/A 36-40 73.64% Mansfield Elem and High School Mansfield Mansfield N/A 36-40 73.64% McKinley Elementary School Yakima Yakima N/A 36-40 73.64% Millwood Early Childhood Center West Valley (Spokane) Spokane N/A 36-40 73.64% Morgan Middle School Ellensburg Ellensburg N/A 36-40 73.64% Morgen Owings Elementary School Lake Chelan Chelan N/A 36-40 73.64%
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Table 11.3–Continued USGS Landfire Return Periods Less Than 50 Years K–12 Facilities Not Within DNR Wildland/Urban Interface Communities
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
Mountainview Elementary School West Valley (Yakima) Yakima N/A 36-40 73.64% Mt. Stuart Elementary School Ellensburg Ellensburg N/A 36-40 73.64% Naches Valley High School Naches Valley Naches N/A 36-40 73.64% Naches Valley Intermediate School Naches Valley Naches N/A 36-40 73.64% Naches Valley Middle School Naches Valley Naches N/A 36-40 73.64% Nespelem Elementary School Nespelem Nespelem N/A 36-40 73.64%
Nob Hill Elementary School Yakima Yakima N/A 36-40 73.64% Oakesdale Elementary School Oakesdale Oakesdale N/A 36-40 73.64% Okanogan High School Okanogan Okanogan N/A 36-40 73.64% Orchard Middle School Wenatchee Wenatchee N/A 36-40 73.64%
Orondo Elementary and Middle School Orondo Orondo N/A 36-40 73.64%
Oroville Middle High School Oroville Oroville N/A 36-40 73.64% Otis Orchards Elementary School East Valley (Spokane) Otis Orchards N/A 36-40 73.64% P C Jantz Elementary School Odessa Odessa N/A 36-40 73.64% Parkway Elementary School Clarkston Clarkston N/A 36-40 73.64% Pioneer Middle School Walla Walla Walla Walla N/A 36-40 73.64% Pioneer Middle School Wenatchee Wenatchee N/A 36-40 73.64% Pomeroy Elementary School Pomeroy Pomeroy N/A 36-40 73.64% Pomeroy Junior Senior High School Pomeroy Pomeroy N/A 36-40 73.64% Preston Hall Middle School Waitsburg Waitsburg N/A 36-40 73.64% Red Rock Elementary School Royal Royal City N/A 36-40 73.64% Republic Elementary School Republic Republic N/A 36-40 73.64% Republic Junior High School Republic Republic N/A 36-40 73.64% Republic Parent Partner Republic Republic N/A 36-40 73.64% Ritzville Grade School Ritzville Ritzville N/A 36-40 73.64% Ritzville High School Ritzville Ritzville N/A 36-40 73.64% Robert E Lee Elementary School Eastmont East Wenatchee N/A 36-40 73.64% Robert S. Lince Elementary School Selah Selah N/A 36-40 73.64% Robertson Elementary School Yakima Yakima N/A 36-40 73.64% Roosevelt Elementary School Yakima Yakima N/A 36-40 73.64% Rosalia Elementary & Secondary Rosalia Rosalia N/A 36-40 73.64% School Royal High School Royal Royal City N/A 36-40 73.64% Royal Middle School Royal Royal City N/A 36-40 73.64% Selah High School Selah Selah N/A 36-40 73.64% Selah Intermediate School Selah Selah N/A 36-40 73.64% Selah Junior High School / Homelink Selah Selah N/A 36-40 73.64% Selah Preschool Selah Selah N/A 36-40 73.64% Seth Woodard Elementary School West Valley (Spokane) Spokane N/A 36-40 73.64% Sheridan Elementary School Spokane Spokane N/A 36-40 73.64% Skill Source Wenatchee Wenatchee N/A 36-40 73.64% Smokiam Alternative High School Soap Lake Soap Lake N/A 36-40 73.64% Soap Lake Elementary School Soap Lake Soap Lake N/A 36-40 73.64% Soap Lake Middle & High School Soap Lake Soap Lake N/A 36-40 73.64% Special Education Preschool Eastmont East Wenatchee N/A 36-40 73.64% Special Education School Wenatchee Wenatchee N/A 36-40 73.64% Special Services Clarkston Clarkston N/A 36-40 73.64% Spokane Skills Center Spokane Spokane N/A 36-40 73.64% Sprague Elementary School Sprague Sprague N/A 36-40 73.64% Sprague High School Sprague Sprague N/A 36-40 73.64% St John Elementary School St. John Saint John N/A 36-40 73.64% St John-Endicott High School St. John Saint John N/A 36-40 73.64% Star Elem School Star Pasco N/A 36-40 73.64% Starbuck School Starbuck Starbuck N/A 36-40 73.64% Steptoe Elementary School Steptoe Steptoe N/A 36-40 73.64% Sterling Intermediate School Eastmont East Wenatchee N/A 36-40 73.64% Summitview Elementary School West Valley (Yakima) Yakima N/A 36-40 73.64%
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Table 11.3–Continued USGS Landfire Return Periods Less Than 50 Years K–12 Facilities Not Within DNR Wildland/Urban Interface Communities
FACILITY INFORMATION WILDFIRE HAZARDS USGS Fire WUI Landfire Probability Community Return within Facility Name District City DNR Fire Period Range 50 Year Hazard (Years) Time Perioda Rating
Sunnyslope Elementary School Wenatchee Wenatchee N/A 36-40 73.64% Thorp Elementary & Junior Senior High Thorp Thorp N/A 36-40 73.64% School Tieton Intermediate School Highland Tieton N/A 36-40 73.64% Vale Elementary School Cashmere Cashmere N/A 36-40 73.64% Valley Academy Of Learning Wenatchee Wenatchee N/A 36-40 73.64% Valley View Elementary School Ellensburg Ellensburg N/A 36-40 73.64% Washington Elementary School Wenatchee Wenatchee N/A 36-40 73.64% Washtucna Elem./H.S. Washtucna Washtucna N/A 36-40 73.64% Waterville Elementary School Waterville Waterville N/A 36-40 73.64% Waterville High School Waterville Waterville N/A 36-40 73.64% Wenatchee High School Wenatchee Wenatchee N/A 36-40 73.64% Wenatchee Valley Technical Skills Wenatchee Wenatchee N/A 36-40 73.64% Center West Valley High School West Valley (Spokane) Spokane N/A 36-40 73.64% West Valley High School West Valley (Yakima) Yakima N/A 36-40 73.64% West Valley High School Freshman West Valley (Yakima) Yakima N/A 36-40 73.64% Campus West Valley Preschool West Valley (Yakima) Yakima N/A 36-40 73.64% Westside Alternative High School Wenatchee Wenatchee N/A 36-40 73.64% Westside High School Wenatchee Wenatchee N/A 36-40 73.64% Whitney Elementary School Yakima Yakima N/A 36-40 73.64% Whitworth Elementary School Mead Spokane N/A 36-40 73.64% Wide Hollow Elementary School West Valley (Yakima) Yakima N/A 36-40 73.64% Wilbur Elementary School Wilbur Wilbur N/A 36-40 73.64% Wilbur Secondary School Wilbur Wilbur N/A 36-40 73.64% Wilson Middle School Yakima Yakima N/A 36-40 73.64% Wishram High And Elementary School Wishram Wishram N/A 36-40 73.64% Yakima Valley Technical Skills Center Yakima Yakima N/A 36-40 73.64% McDonald Elementary School Central Valley Spokane N/A 46-50 65.10% North Pines Middle School Central Valley Spokane N/A 46-50 65.10% Prairie View Elementary School Mead Spokane N/A 46-50 65.10% Reardan Elementary School Reardan-Edwall Reardan N/A 46-50 65.10% Reardan Middle Senior High School Reardan-Edwall Reardan N/A 46-50 65.10% Reardan Online Academy Reardan-Edwall Reardan N/A 46-50 65.10% Trent Elementary School East Valley (Spokane) Spokane Valley N/A 46-50 65.10% a Landfire Return Periods/Probabilities should not be interpreted literally, but rather as a measure of relative fire hazard level. See discussion in subsection 11.5. The statement that the USGS Landfire Return periods should not be interpreted literally is based on a comparison of the estimates in Tables 11.2 and 11.3 which show more that than 500 K–12 campuses are within communities with estimated 50-year burn probabilities of 60 percent or higher. In contrast, the historical fire record over the past several decades shows that very few, if any, K–12 campuses in Washington have been affected by wildland/urban fires. The USGS Landfire Return Period data are better interpreted as an indication of the likelihood of a fire near a given location rather than the burn probability at a given location. Further insight into the apparent discordance between the USGS Landfire Return Period estimates and the historical record in Washington requires additional analysis by fire professionals.
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As noted previously, the data and estimates in the above tables represent only a first step in evaluating the wildland/urban interface fire risk for K–12 facilities. The facilities listed in the above tables may have significant wildland/urban interface fire risk. More accurate evaluation of wildland/urban interface fire risk, for any given campus, requires a site-specific evaluation that includes all of the risk factors listed previously:
Vegetative fuel loads adjacent and near the campus, including fuel types, fuel density, and proximity of high fuel load areas to the campus.
Topography.
Climate.
Ignition sources and frequency of fire ignitions.
Local fire suppression resources (fire agency response time, resources of crews and apparatus, and water supplies).
Extent to which campus buildings have fire-safe construction and defensible space. Evaluation of the above characteristics may require technical advice and support from fire professionals, including local fire agency staff or other fire experts. In general, K–12 campuses probably have a significantly lower wildland/urban interface fire risk than single family residential buildings for several reasons including:
K–12 facilities are unlikely to be deeply embedded in heavily forested areas unlike many single family residences.
K–12 campuses typically have much larger areas of low fuel load than single family residences such as mowed grassy areas and paved areas.
Fire suppression agencies may place a higher priority on protecting K–12 facilities than single family residences. The assertion that K–12 campuses may have a significantly lower wildland/urban interface fire risk than single family residences appears to be supported by the historical fire loss record as discussed in Section 11.3. Since 1985, wildland/urban or wildland fires have destroyed about 439 homes, but there is no documentation that any K–12 facilities have been destroyed.
11.6 Wildland/Urban Fires: Potential Loss Estimates for K–12 Facilities Based on the discussion of fire hazard data in the previous section, it does not appear that there are enough data to make probabilistic estimates for wildland/urban interface fire losses for K–12 facilities. However, the probability of a single K–12 campus being destroyed, while certainly not zero, appears to be very low. Although it is possible that a large wildland/urban interface fire could destroy more than one campus, the likelihood of such events appears very low. Damage from wildland/urban interface
Page | 224 fires, to one or more campuses, is more likely than complete destruction but still appears to have a low probability. An important caveat on the above qualitative conclusions is that they are based on limited statewide data. There may be some K–12 campuses with moderate, high, or even very high risk from wildland/urban interface fires. However, site-specific evaluations, on a campus-by-campus basis, are necessary to determine which campuses may have substantial risk from wildland/urban interface fires. The potential losses to schools from wildland/urban interface fires are proportional to the number of campuses burned, the square footage of the buildings on a given campus, and the replacement value of buildings and contents. The average K–12 campus in Washington has nearly 68,000 SF of buildings, with an average building replacement value of approximately $300/SF. These data yield an average building replacement value per campus of about $20 million. The average replacement value of contents is about five percent of building replacement value, which brings the total average value at risk to about $21 million per campus. The vast majority of homes that are ignited by wildland/urban interface fires are a complete loss. For school campuses that are ignited, the fraction that are a complete loss may be somewhat lower than for homes, because of the likelihood that fire suppression resources will be focused on larger, more important buildings, such as schools. A rough estimate is that the fire damage for schools affected by wildland/urban interface is likely to be at least 50 percent of replacement value, and perhaps much closer to 100 percent. The corresponding ranges of losses are shown in Table 11.4.
Table 11.4 Potential Losses for Wildland/Urban Interface Fires Affecting K-12 Campuses
Number of Damage Estimates Death Estimates Fire Event Campuses Low Range High Range Low Range High Range Small, localized area 1 $10,500,000 $21,000,000 None Less than 5 Medium, affectung a large 5 $52,500,000 $105,000,000 None Less than 50 part of a community Large, affecting several 10 $105,000,000 $210,000,000 None More than 100 communities The most likely number of deaths from wildland/urban interface fires of any size is none – that is, in almost all cases evacuation to safe areas is possible before a campus is ignited. However, deaths are possible if evacuation is incomplete or in the unlikely possibility that all evacuation routes from a campus are blocked by fire before evacuation is completed. Overall, the risk of deaths or injuries from wildland/urban interface fires affecting K–12 facilities is very low.
11.7 Mitigation Strategies for Wildland/Urban Interface Fires This section summarizes common strategies for reducing the level of fire risk to both property and life safety in wildland/urban interface areas. These strategies have four elements: 1) Reduce the probability of fire ignitions, 2) Reduce the probability that small fires will spread, 3) Minimize property damage, and 4) Minimize life safety risk.
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School districts are not responsible for fire suppression or community-wide mitigation measures for wildland/urban interface fires. These are the responsibility of cities, counties, and fire agencies. For districts with campuses determined to be at significant risk from wildland/urban interface fires, there are three types of mitigation measures that may be practical including:
For life safety, develop and practice effective evacuation plans for wildland/urban interface fires.
For existing facilities with significant risk: o Maintain the maximum possible defensible space around buildings. o Implement fire-safe improvements such as non-flammable roofs and covering vent openings and overhangs with wire mesh to prevent entry and trapping of embers etc.
Whenever possible, site new facilities outside of areas with high risk of wildland/urban interface fires, include fire-safe features in the design and ensure the maximum possible defensible space around new buildings. Mitigation projects for wildland/urban interface fire may be eligible for FEMA and other grant funding including:
Defensible space activities.
Hazardous fuel reduction activities.
Ignition resistant construction activities.
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Chapter Twelve: Landslides
12.1 Landslide Overview and Definitions The term “landslide” refers to a variety of slope instabilities that result in the downward and outward movement of slope-forming materials including rocks, soils, and vegetation. Many types of landslides are differentiated based on the types of materials involved and the mode of movement. The descriptive nomenclature for landslides is summarized in the following figure.
Figure 12.1 Landslide Nomenclature1
Debris flows and mudslides (mudflows) are often differentiated from the other types of landslides, for which the sliding material is predominantly soil and/or rock. Debris flows and mudslides typically have high water content and may behave similarly to floods. However, debris flows may be much more destructive than floods because of their higher densities, high debris loads, and high velocities. There are three main factors that determine susceptibility (potential) for landslides: 1) Slope, 2) Soil/rock characteristics, and 3) Water content.
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Figure 12.2 Major Types of Landslides1
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Steeper slopes are more prone to all types of landslides. Loose, weak rock or soil is much more prone to landslides than competent rocks or dense, firm soils. Water saturated soils or rocks, with a high water table, are much more prone to landslides because the water pore pressure decreases the shear strength of the soil or rock and thus increases the probability of sliding. Most landslides occur during rainy months when soils are saturated with water. As noted previously, the water content of soils or rock is a major factor in determining the likelihood of sliding for any given landslide-prone location. However, landslides may occur at any time of year, including both dry and rainy months. Landslides are also commonly initiated by earthquakes. Areas prone to seismically triggered landslides are exactly the same as those prone to ordinary (non-seismic) landslides. As with ordinary landslides, seismically triggered landslides are more likely to originate from earthquakes that occur when soils are saturated with water. Any type of landslide may result in damages or complete destruction of buildings in their path as well as deaths and injuries for building occupants. Landslides frequently cause road blockages (by depositing debris on road surfaces) or road damage (if the road surface itself slides downhill). Utility lines and pipes are also prone to breakage in slide areas. On March 22, 2014 a major landslide on a steep slope above the North Fork of the Stillaguamish River buried a rural community near Oso, Washington. This landslide destroyed about 50 homes, blocked about 1 mile of State Highway 530, and resulted in 43 deaths, the most deaths ever recorded from a landslide in Washington. The area of the 2014 slide had a smaller landslide in 2006, and the surrounding area also has a history of landslides going back to the 1940s. The 2014 landslide was much larger than previous landslides in the area, with the debris flow crossing the Stillaguamish River, burying the community and highway on the south side of the river. The following figures show the landslide vicinity before and after the landslide.
Figure 12.3 Oso Landslide (March 22, 2014)
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Figure 12.4 Oso Landslide Vicinity (Before Landslide)
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The following figures show additional examples of recent landslides in Washington.
Figure 12.5 Rolling Bay, Bainbridge Island 19972
Figure 12.6 Road 170 Near Basin City 20063
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Figure 12.7 Highway 410 Near Town of Nile 20093
12.2 Landslide Hazard Mapping and Hazard Assessment There are two approaches to landslide hazard mapping and hazard assessment:
Mapping historical landslides that also provide an indication of the potential for future landslides.
Landslide studies by geotechnical engineers to estimate the potential for future landslides. The Washington Department of Natural Resources has mapped known historical landslides in Washington. This map is shown in Figure 12.8 on the following page. Landslide mapping is almost always incomplete because it is difficult to find all landslides especially in remote heavily forested areas. Nevertheless, the historical landslide map gives a general idea of Washington locations that are most prone to landslides. Maps of areas within Washington, with moderate or high landslide incidence and landslide potential, are shown in Figures 12.9 and 12.10. A more accurate understanding of landslide hazard for a given school building requires a more detailed landslide hazard evaluation by a geotechnical engineer. Such site-specific studies evaluate the slope, soil/rock, and groundwater characteristics at specific sites. Such assessments often require drilling to determine subsurface soil/rock characteristics. In areas with moderate to
Page | 232 high landslide potential, detailed site-specific landslide assessments are often conducted prior to development of projects to evaluate the level of landslide hazard at the development site. Detailed site-specific landslide hazard assessments may also be conducted to determine the level of landslide hazard at locations where the risk appears high enough to warrant more detailed evaluations. An important caveat for landslide hazard assessments is that even with detailed site-specific evaluations by a geotechnical engineer, there is considerable inevitable uncertainty. That is, it is very difficult to make quantitative predictions of the likelihood or the size of future landslide events. In some cases, landslide hazard assessments by more than one geotechnical engineer may reach conflicting opinions. These limitations and uncertainties notwithstanding, a detailed site-specific landslide hazard assessment does provide the best available information about the likelihood of future landslides. For example, such studies can provide enough information to determine that the landslide risk is higher at one location than another location and thus provide meaningful guidance for siting future development. Given the above considerations, landslide hazard and risk assessments are generally qualitative or semi-quantitative in nature.
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Figure 12.8 DNR Mapped Landslides4
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Figure 12.9 Landslide Incidence and Potential2
High Incidence: >15 percent of area involved Moderate Incidence: 1.5–15 percent of area involved Low Incidence: <1.5 percent of area involved High Susceptibility Moderate Susceptibility
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Figure 12.10 Department of Natural Resources – Landslide Potential Map5
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12.3 Landslide Hazard and Risk Assessments for K–12 Facilities High risk areas for landslides are locations where landslides have occurred in the past or appear likely to occur in the future, and there are buildings or infrastructure in these areas. The overlap of landslide hazard areas with developed areas is what results in risk – that is, threats to people, buildings and infrastructure. Table 12.1 on the following pages summarizes a preliminary landslide hazard and risk assessment for K–12 facilities. The table contains two sets of information:
The 15 K–12 facilities within 500 feet of DNR mapped historical landslides.
K–12 facilities with estimated maximum slopes in the immediate vicinity of the campus greater than 20 percent. The preliminary landslide hazard and risk assessments are based on the following criteria for the maximum slope in the immediate vicinity of a campus:
High – Slope > 40 percent
Moderate – Slope between 30 and 40 percent
Low – Slope between 20 and 30 percent
Very Low – Slope < 20 percent Slopes in the immediate vicinity of each campus were calculated from digital elevation data for the campus and for a grid of points 90 meters, 180 meters, and 270 meters from the campus location in north, south, east, and west directions. The 90-meter intervals for slope calculations were chosen to be commensurate with the digital elevation data which has a 30 meter spacing. The following two measures of landslide hazard provide only a preliminary assessment of landslide hazard and the corresponding risk to K–12 facilities for which these parameters apply. They are a) location within 500 feet of DNR mapped landslides and b) slopes > 20 percent. The preliminary screening for landside hazard summarized in Table 12.1 should be interpreted cautiously as an indication of possible landslide hazards, and it is neither a definitive determination of landslide hazards nor the level of landslide risk. Without a more detailed site- specific evaluation of landslide hazards and risk for each campus, it is not possible to make quantitative estimates of the level of risk for each campus. Qualitatively, for a given campus or a given building, landslide damages can range from very minor damage to complete destruction. Similarly, the numbers of deaths and injuries can range from none, to many dozens (or more) for large slides that occur without warning while a campus or building is highly populated.
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Table 12.1 Preliminary Landslide Hazard and Risk Assessment
FACILITY INFORMATION LANDSLIDE HAZARDS Landslides Approximate within 500 Preliminary Maximum Slope Facility Name District City feet of DNR Landslide in Vicinity of Mapped Risk Level Campus Landslides? (percent) Endeavour Elementary School Issaquah Issaquah YES Low 29% South Colby Elementary School South Kitsap Port Orchard YES Low 28% Carrolls Elementary School Kelso Kelso YES Low 27% Stevenson High School Stevenson-Carson Stevenson YES Low 26% Pacific Cascade Freshman Campus Issaquah Issaquah YES Low 26% Woodland High School Woodland Woodland YES Low 24% Pacific Cascade Middle School Issaquah Issaquah YES Low 23% South Kitsap High School South Kitsap Port Orchard YES Low 21% Fauntleroy Elementary School Seattle Seattle YES Low 20% White Center Heights Elementary Highline Seattle YES Very Low 19% Gatewood Elementary School Seattle Seattle YES Very Low 17% Stevenson Elementary School Stevenson-Carson Stevenson YES Very Low 14% Onion Creek Elementary School Onion Creek Colville YES Very Low 12% Kaplan Academy of Washington Stevenson-Carson Stevenson YES Very Low 10% Mt. Solo Middle School Longview Longview YES Very Low 5% Stehekin Elementary School Stehekin Stehekin NO High 70% Holmes Elementary School Spokane Spokane NO High 60% Wishram High And Elementary School Wishram Wishram NO High 60% Asotin Junior Senior High School Asotin-Anatone Asotin NO High 59% Leonard M Jennings Elementary School Colfax Colfax NO High 57% Holden Village Community School Lake Chelan Chelan NO High 57% Wishkah Valley Elementary High School Wishkah Valley Aberdeen NO High 51% Evergreen School Evergreen (Stevens) Gifford NO High 51% Cape Flattery Preschool Cape Flattery Sekiu NO High 50% Toutle Lake High School Toutle Lake Toutle NO High 48% Queen Anne Elementary School Seattle Seattle NO High 47% Toutle Lake Elementary School Toutle Lake Toutle NO High 46% White Pass Junior Senior High School White Pass Randle NO High 46% Columbia Virtual Academy-Orient Orient Orient NO High 45% Kahlotus Elementary & High School Kahlotus Kahlotus NO High 44% Orient Elementary School Orient Orient NO High 44% Fairwood Elementary School Kent Renton NO High 44% Victor Falls Elementary School Sumner Bonney Lake NO High 43%
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Table 12.1–Continued Preliminary Landslide Hazard and Risk Assessment
FACILITY INFORMATION LANDSLIDE HAZARDS Landslides Approximate within 500 Preliminary Maximum Slope Facility Name District City feet of DNR Landslide in Vicinity of Mapped Risk Level Campus Landslides? (percent) Fidalgo Elementary School Anacortes Anacortes NO High 42% Selkirk Elementary School Selkirk Metaline Falls NO High 42% Washington Virtual Academy Omak Omak Omak NO High 41% Elem./M.S./H.S. Yale Elementary School Woodland Ariel NO High 41% Inchelium Elementary School Inchelium Inchelium NO High 41% Inchelium High School Inchelium Inchelium NO High 41% Inchelium Middle School Inchelium Inchelium NO High 41% Washington Elementary School Centralia Centralia NO High 41% Home School Program (REACH) Methow Valley Winthrop NO High 40% Methow Valley Elementary School Methow Valley Winthrop NO High 40% Trout Lake School Trout Lake Trout Lake NO Moderate 39% Sherman Elementary School Tacoma Tacoma NO Moderate 38% Beaver Valley School Cascade Plain NO Moderate 38% Tumwater Hill Elementary School Tumwater Tumwater NO Moderate 38% Beaver Valley School Cascade Leavenworth NO Moderate 38% Klickitat Elementary & High School Klickitat Klickitat NO Moderate 38% Wade King Elementary School Bellingham Bellingham NO Moderate 38% Mo Junior High/Aldercrest School Shoreline Seattle NO Moderate 36% Beacon Hill International School Seattle Seattle NO Moderate 35% Pateros High School Pateros Pateros NO Moderate 35% Okanogan High School Okanogan Okanogan NO Moderate 35% Talbot Hill Elementary School Renton Renton NO Moderate 35% Juanita Elementary School Lake Washington Kirkland NO Moderate 35% Colfax High School Colfax Colfax NO Moderate 34% Kennydale Elementary School Renton Renton NO Moderate 34% East Valley High School East Valley (Spokane) Spokane Valley NO Moderate 34% Pomeroy Junior Senior High School Pomeroy Pomeroy NO Moderate 34% Willapa Valley Middle High School Willapa Valley Raymond NO Moderate 33% Developmental Preschool Willapa Valley Menlo NO Moderate 33% Selkirk High School Selkirk Ione NO Moderate 33% Selkirk Junior Senior High School Selkirk Ione NO Moderate 33% Selkirk Middle School Selkirk Ione NO Moderate 33% Olympic View Middle School Mukilteo Mukilteo NO Moderate 33%
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Table 12.1–Continued Preliminary Landslide Hazard and Risk Assessment
FACILITY INFORMATION LANDSLIDE HAZARDS Landslides Approximate within 500 Preliminary Maximum Slope Facility Name District City feet of DNR Landslide in Vicinity of Mapped Risk Level Campus Landslides? (percent) Franklin Elementary School Spokane Valley NO Moderate 33% Columbia Virtual Academy Valley Wilkeson NO Moderate 33% Wilkeson Elementary School White River Republic NO Moderate 33% Republic Senior High School Republic Republic NO Moderate 32% Republic Elementary School Republic Republic NO Moderate 32% Republic Junior High School Republic Republic NO Moderate 32% Republic Parent Partner Republic Mtlk Terrace NO Moderate 32% Challenge Elementary School Edmonds Tukwila NO Moderate 32% Tukwila Elementary School Tukwila Wellpinit NO Moderate 32% Wellpinit High School Wellpinit Tacoma NO Moderate 32% Willard Elementary School Tacoma Ephrata NO Moderate 31% Parkway School Ephrata Kalama NO Moderate 31% Kalama Elem School Kalama Kalama NO Moderate 31% Kalama Junior Senior High School Kalama Hoquiam NO Moderate 31% Lincoln Elementary School Hoquiam Curlew NO Moderate 31% Curlew Alternative School Curlew Curlew NO Moderate 31% Curlew Parent Partner Curlew Federal Way NO Moderate 31% Nautilus K-8 School Federal Way Federal Way NO Moderate 30% Washington Elementary School Hoquiam South Bend NO Moderate 30% South Bend High School South Bend Arlington NO Moderate 30% Post Middle School Arlington Bellevue NO Moderate 30% Puesta del Sol Elementary School Bellevue Bellingham NO Moderate 30% Sehome High School Bellingham Keller NO Moderate 30% Keller Elementary School Keller Seattle NO Moderate 30% Beverly Park Elem at Glendale Highline South Bend NO Moderate 30% Chauncey Davis Elementary School South Bend Auburn NO Low 29% Chinook Elementary School Auburn Tacoma NO Low 29% Northeast Tacoma Elementary School Tacoma Seattle NO Low 29% Van Asselt Elementary School Seattle Seattle NO Low 29% Leschi Elementary School Seattle La Center NO Low 28% La Center High School La Center Index NO Low 28% Index Elementary School Index Belfair NO Low 28% Belfair Elementary School North Mason Belfair NO Low 28%
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Table 12.1–Continued Preliminary Landslide Hazard and Risk Assessment
FACILITY INFORMATION LANDSLIDE HAZARDS Landslides Approximate within 500 Preliminary Maximum Slope Facility Name District City feet of DNR Landslide in Vicinity of Mapped Risk Level Campus Landslides? (percent) Lakeland Hills Elementary School Auburn Auburn NO Low 28% Residential Consortium Seattle Seattle NO Low 28% Curlew Elementary & High School Curlew Curlew NO Low 28% Bear Creek Elementary School Northshore Woodinville NO Low 27% Marvista Elementary School Highline Normandy Park NO Low 27% Skykomish Elementary School Skykomish Skykomish NO Low 27% Lincoln Elementary School Mount Vernon Mount Vernon NO Low 27% Friday Harbor Middle School San Juan Island Friday Harbor NO Low 27% Morton Elementary School Morton Morton NO Low 26% Evergreen High School Highline Seattle NO Low 26% Whitworth Elementary School Seattle Seattle NO Low 26% Ilalko Elementary School Auburn Auburn NO Low 26% Kent Prairie Elementary School Arlington Arlington NO Low 26% North Elementary School Moses Lake Moses Lake NO Low 26% Waldron Island School Orcas Island Waldron Island NO Low 26% Skykomish High School Skykomish Skykomish NO Low 26% Cooper Elementary School Seattle Seattle NO Low 25% Viewlands Elementary School Seattle Seattle NO Low 25% North Olympic Peninsula Skills Center Port Angeles Port Angeles NO Low 25% Chelan High School Lake Chelan Chelan NO Low 25% Chambers Elementary School University Place University Pla NO Low 25% La Center Elementary School La Center La Center NO Low 25% Creekside Elementary School Issaquah Sammamish NO Low 25% Evergreen Elementary School Shelton Shelton NO Low 25% Martin Luther King Elementary School Vancouver Vancouver NO Low 25% Hazelwood Elementary School Renton Newcastle NO Low 25% Lincoln Elementary School Olympia Olympia NO Low 25% Sunrise Elementary School Kent Kent NO Low 25% Sacajawea Elementary School Seattle Seattle NO Low 24% Schmitz Park Elementary School Seattle Seattle NO Low 24% Valley School Valley Valley NO Low 24% Butler Acres Elementary School Kelso Kelso NO Low 24% Mary Walker Alternative High School Mary Walker Springdale NO Low 24%
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Table 12.1–Continued Preliminary Landslide Hazard and Risk Assessment FACILITY INFORMATION LANDSLIDE HAZARDS Landslides Approximate within 500 Preliminary Maximum Slope Facility Name District City feet of DNR Landslide in Vicinity of Mapped Risk Level Campus Landslides? (percent) Omak Alternative High School Omak Omak NO Low 24% Hilltop Elementary School Highline Seattle NO Low 23% Melvin G Syre Elementary School Shoreline Shoreline NO Low 23% Mukilteo Elementary School Mukilteo Mukilteo NO Low 23% Hilder Pearson Elementary School North Kitsap Poulsbo NO Low 23% Pomeroy Elementary School Pomeroy Pomeroy NO Low 23% Griffin Home Renton Renton NO Low 23% Shelton View Elementary School Northshore Bothell NO Low 23% Blackwell Elementary School Lake Washington Sammamish NO Low 23% Orca K-8 School Seattle Seattle NO Low 23% Kimball Elementary School Seattle Seattle NO Low 23% Roosevelt Middle School - Old Port Angeles Port Angeles NO Low 23% Lincoln High School Port Angeles Port Angeles NO Low 22% Wahkiakum High School Wahkiakum Cathlamet NO Low 22% Boren School Seattle Seattle NO Low 22% Dearborn Park Elementary School Seattle Seattle NO Low 22% Chief Sealth High School Seattle Seattle NO Low 22% Center Elementary School Grand Coulee Dam Grand Coulee NO Low 22% Bryn Mawr Elementary School Renton Seattle NO Low 22% Naselle-Grays River Naselle Youth Camp School Naselle NO Low 22% Valley Showalter Middle School Tukwila Seattle NO Low 22% Thomas Jefferson High School Federal Way Auburn NO Low 22% White River High School White River Buckley NO Low 22% Julius A Wendt Elementary/John C Wahkiakum Cathlamet NO Low 22% Thomas Middle School Cascade High School Cascade Leavenworth NO Low 22% Sanislo Elementary School Seattle Seattle NO Low 22% Russell Ridge Center Tahoma Maple Valley NO Low 22% Manson Junior Senior High School Manson Manson NO Low 22% Bremerton Offices Bremerton Bremerton NO Low 22% Green Mountain School Green Mountain Woodland NO Low 22% Henderson Bay Alt High School Peninsula Gig Harbor NO Low 22%
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Table 12.1–Continued Preliminary Landslide Hazard and Risk Assessment
FACILITY INFORMATION LANDSLIDE HAZARDS Landslides Approximate within 500 Preliminary Maximum Slope Facility Name District City feet of DNR Landslide in Vicinity of Mapped Risk Level Campus Landslides? (percent) Lyle Middle School Lyle Lyle NO Low 22% Hoquiam Middle School Hoquiam Hoquiam NO Low 21% Brinnon Elementary School Brinnon Brinnon NO Low 21% Bellevue High School Bellevue Bellevue NO Low 21% Dimmitt Middle School Renton Seattle NO Low 21% Mount Pleasant Elementary School Mount Pleasant Washougal NO Low 21% Edmonds Elementary School Edmonds Edmonds NO Low 21% Madrona Nongraded School Edmonds Edmonds NO Low 21% Maple Elementary School Seattle Seattle NO Low 21% Starbuck School Starbuck Starbuck NO Low 21% Emerson Elementary School Hoquiam Hoquiam NO Low 21% Issaquah Special Services Issaquah Issaquah NO Low 21% Lakeridge Elementary School Renton Seattle NO Low 21% Prosser Heights Elementary School Prosser Prosser NO Low 21% Briarcliff Elementary School Seattle Seattle NO Low 21% Fairmount Park Elementary School Seattle Seattle NO Low 21% Stevens Elementary School Seattle Seattle NO Low 21% Cedar River Middle School Tahoma Maple Valley NO Low 21% Lake Louise Elementary School Clover Park Lakewood NO Low 21% West Queen Anne Elementary Seattle Seattle NO Low 21% Toledo High School Toledo Toledo NO Low 21% Manson Elementary School Manson Manson NO Low 21% Franklin Elementary School Pullman Pullman NO Low 21% Lakes High School Clover Park Lakewood NO Low 21% Panther Lake Elementary School Kent Kent NO Low 21% Alliance Academy Bremerton Bremerton NO Low 21% Great Northern Elementary School Great Northern Spokane NO Low 21% Breidablik Elementary School North Kitsap Poulsbo NO Low 20% Stillaguamish School Arlington Arlington NO Low 20% Okanogan Middle School Okanogan Okanogan NO Low 20% Winlock Miller Elementary School Winlock Winlock NO Low 20% J.M. Weatherwax High School Aberdeen Aberdeen NO Low 20% Terrace Park Elementary School Edmonds Mtlk Terrace NO Low 20%
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Table 12.1–Continued Preliminary Landslide Hazard and Risk Assessment
FACILITY INFORMATION LANDSLIDE HAZARDS Landslides Approximate within 500 Preliminary Maximum Slope Facility Name District City feet of DNR Landslide in Vicinity of Mapped Risk Level Campus Landslides? (percent) Lowell Elementary School Everett Everett NO Low 20% Sunnyside Elementary School Marysville Marysville NO Low 20% Auburn Riverside High School Auburn Auburn NO Low 20% Boyer Clinic Highline Seattle NO Low 20% Enterprise Elementary School Federal Way Federal Way NO Low 20% Emerson Elementary School Snohomish Snohomish NO Low 20% Crescent Heights Elementary School Tacoma Tacoma NO Low 20% Lakeside Middle School Nine Mile Falls Nine Mile Falls NO Low 20% Columbia High And Elementary School Columbia (Stevens) Hunters NO Low 20% Franklin Elementary School Port Angeles Port Angeles NO Low 20% Roosevelt Elementary School Tacoma Tacoma NO Low 20% Kitsap Lake Elementary School Bremerton Bremerton NO Low 20% Shaw Island Elementary School Shaw Island Shaw Island NO Low 20% Renaissance Alternative High School Bremerton Bremerton NO Low 20%
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12.4 Mitigation of Landslide Risk Mitigation of landslide risks is often difficult from both the engineering and cost perspectives. In many case, there may be no practical landslide mitigation measure. In some cases, mitigation may be possible. Typical landslide mitigation measures include:
Slope stability can be improved by addition of drainage to reduce pore water pressure and/or by slope stabilization measures including retaining walls, rock tie-backs with steel rods, and other geotechnical methods.
For smaller landslides or debris flows, protection for existing facilities at risk may be increased by building diversion structures to deflect landslides or debris flows around a facility at risk.
For very high risk facilities, with a high degree of life safety risk, abandoning the facility and replacing it with a new facility may be the only possible landslide mitigation measures.
For new construction, siting facilities outside of landslide hazard areas is the most effective mitigation measure.
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Chapter Thirteen: Other Natural Hazards The previous six chapters address natural hazards which pose the greatest risks for K–12 facilities in Washington. Those risks are 1) earthquakes, 2) tsunamis, 3) volcanic hazards, 4) floods, 5) wildland/urban interface fires and 6) landslides. In addition to the six major hazards there are other natural hazards which generally pose less risk to K–12 facilities and/or risk to only a very small number of K–12 facilities. This chapter addresses three other natural hazards that are addressed in the 2013 Washington State Enhanced Hazard Mitigation Plan. Those risks are 1) avalanche, 2) drought and 3) severe weather. For completeness, this chapter also includes a brief commentary on two other hazards 1) climate change and 2) subsidence.
13.1 Avalanches Avalanches occur in areas with high slopes and large accumulations of snow and ice. Avalanches happen when snow and ice become unstable and slides rapidly downslope. They pose very high levels of life safety to people in their path and may result in severe damage or destruction to buildings as well as road and highway closures. The following figure shows mountainous areas of Washington with elevations above 2,000 feet. Most, but not all, avalanches occur in areas above this elevation.
Figure 13.1 Elevations Above 2,000 Feet in Washington1
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Deaths from avalanches in Washington State have averaged about three per year1 with nearly all these deaths occurring to back country recreationists. Detailed statewide mapping of avalanche hazard zones is not available; therefore, if any K–12 facilities are subject to avalanche hazards, it is currently unknown. Most likely, there may be a very small number of K–12 facilities at risk or none. Without statewide mapping of avalanche hazards, hazard and risk assessments must be done on a facility by facility basis. K–12 facilities downslope, from steep slopes, with substantial accumulations of snow and ice may be at risk. Historical avalanche events on such slopes are a strong indicator of possible risk, but avalanches may also occur on slopes with no history of avalanches during time periods of unusually heavy snow and ice accumulations. Possible mitigation measures for K–12 facilities at risk from avalanches include:
Proactive avalanche abatement–triggering small avalanches to prevent large accumulations of snow and ice.
Building diversion barriers to direct avalanches away from at-risk facilities.
Relocation of at-risk facilities outside of locations at risk from avalanches.
13.2 Drought Drought is defined as a prolonged period of lower than normal precipitation that is severe enough to reduce soil moisture, water and snow levels below the minimums necessary for sustaining plant, animal and economic systems. Drought is a significant concern in many communities in Washington especially east of the Cascades. Drought is of greatest concern for communities heavily depending on irrigation for agricultural production. Figure 13.2 shows drought susceptibility in Washington by county. The map of drought susceptibility includes both climate conditions and the severity of drought impacts on counties that may be affected by droughts. For most school districts, the most likely impact of drought is recommended or mandatory water conservation measures. This may include restrictions on how much irrigation water is allowed or prohibit irrigation entirely. Only in extreme droughts would water restrictions be severe enough to limit the availability of water for drinking, cooking or sanitary purposes. In many districts, water may be provided to K–12 facilities by more than one water utility. Utilities may be affected differently by drought conditions depending on each utility’s water source(s). Thus, the severity of drought impacts on K–12 facilities may vary significantly from facility to facility.
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Figure 13.2 Drought Susceptibility for Washington State1
For most school districts and most K–12 facilities, the impacts of future droughts are likely to be relatively minor. However, for districts or facilities that depend on a single well or a small number of wells for water supplies, more severe impacts are possible. The worst case scenario, which is probably unlikely, would be unavailability of water for drinking, cooking or sanitary purposes. In this case, alternative supplies of water would have to be developed including trucking water to K–12 facilities and/or developing alternative water sources via drilling new wells or adding interties to another water system.
13.3 Severe Weather Severe weather events are possible throughout Washington State including high winds, snow storms, ice storms, thunderstorms, hail and tornadoes. Most such events have at most minor impacts on K–12 facilities; although, more severe events may result in significant damages. Of these types of weather hazards, high winds pose the greatest risk to K–12 facilities; although, the level of risk to most facilities is much lower than from the six major hazards addressed in previous chapters.
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High Winds High wind events can occur anywhere in Washington, but the most severe events have occurred on the Pacific Coast and in the Cascades. The following map from the 2013 Washington State Enhanced Hazard Mitigation plan shows that nearly all counties in the state are deemed at significant risk from high wind events.
Figure 13.3 Counties Most Vulnerable to High Winds1
The most common impacts from high wind events are loss of electric power from downed overhead power lines due to tree falls or wind loading on power lines. Damage to buildings is typically limited to minor roof damage from wind or from tree falls onto buildings. More severe events such as the 1962 Columbus Day windstorm result in more widespread damage to vulnerable buildings. Most K–12 facilities will suffer little or no damage in minor to moderate windstorms, with higher levels of damage mostly limited to very severe wind events, especially for the most vulnerable buildings such as portables that are not adequately tied down.
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Snow and Ice Storms Numerous snow and ice storms occur in Washington State every year. The principal impacts from severe storms are disruption of electric power from downed overhead lines and disruption of transportation. Severe snow or ice storms result in school closures but rarely result in significant damage to school facilities. In severe storms, with unusually heavy loading of snow and/or ice, a few very vulnerable buildings may collapse. Most school buildings have been designed for snow loads and are unlikely to suffer significant damage except for extreme events with snow and/or ice loads well above the design loads. Districts with older buildings, especially large span buildings, in areas with high annual snowfalls may wish to evaluate some buildings for the capacity to withstand snow and ice loads on the roofs.
Thunderstorms and Hail Storms Thunderstorms and hail storms occur fairly frequently in Washington State although the frequency and severity of such events is much lower than in many parts of the United States. Severe thunderstorms may have high enough winds to result in downed overhead electric lines and tree falls with disruptions to utilities and transportation. However, the likelihood of thunderstorms severe enough to result in significant damage to K–12 facilities appears very low. Hail storms may occur anywhere in Washington but are more common in eastern Washington. Hail storms with large diameter hail may cause significant damage to exposed vehicles and localized damage to some roofs. However, the likelihood of hail storms severe enough to result in significant damage to K–12 facilities appears extremely low.
Tornadoes Between 1954 and 2012, nearly 100 tornadoes have been reported in Washington State as shown in Figure 13.4 on the following page. The vast majority of these tornadoes were small F0 or F1 on the Fujita Scale or EF-0 or EF-1 on the Enhanced Fujita Scale. Such small tornadoes often result in minor roof damage but do not generally cause significant damage to buildings and rarely result in significant injuries or deaths. The most severe tornado outbreak in Washington occurred in April 1972. An F3 tornado hit Vancouver with six deaths, about 300 injuries, and about $50 million in damages. On this same day there was a F3 near Spokane and a F2 in rural Stevens County. For K–12 facilities the risk of significant damage and casualties from tornadoes is very low, but not zero. Given the low level of risk, mitigation measures such as building safe rooms are not practical or cost-effective. However, district emergency planning should include identifying the best available safe area in each school if a tornado were to occur. Safe areas include a small, interior room with no windows or the fewest possible windows.
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Figure 13.4 Washington State Tornadoes Since 1950
Extreme Temperatures Extreme cold or extreme heat both pose some risks to students and staff, especially for those that walk or bicycle to/from school. Proactive decisions to close schools are sometimes made for periods of either extreme cold or extreme heat. Closures during extreme heat are more likely for schools without air conditioning. Extreme temperatures also pose some risk to school facilities in several ways:
Heating and air conditioning systems in schools are more prone to equipment failures at times of extreme demand such as during periods of extreme temperatures.
Water pipes in poorly insulated school buildings may freeze during periods of extreme cold and result in burst pipes and water damage.
Utility systems providing electric power and water to schools are also more prone to failures during periods of extreme temperatures: o Electric power systems have more failures during periods of either extreme cold or extreme heat, and power outages may require school closures depending on the duration of the outage.
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o Potable water systems may suffer damage during periods of extreme cold, especially small, rural systems with small diameter water pipes with low water flow rates. Loss of water supply typically necessitates school closures. Mitigation Measures for Severe Weather For the most part, addressing severe weather is more in the domain of emergency planning than mitigation planning. Emergency planning measures include developing and practicing responses for events (such as tornado warnings) that may require shelter in place or events (such as power outages, loss of water service, or loss of air conditioning during periods of extreme heat), that may require evacuations and transportation planning. Possible mitigation measures for severe weather events include:
High Wind Events. o Tie-downs for portable buildings. o Increased tree trimming near above ground electric power lines feeding a school or large trees near school buildings. o Installing wind-resistant roofing materials for schools in high wind areas or with a history of wind damage to roofs.
Snow and Ice Storms. o Increased tree trimming as noted above under High Wind Events. o Evaluate and possibly retrofit older buildings, especially large span buildings, that may have been designed for inadequate snow loads.
Extreme Temperatures. o Maintain heating and cooling systems in good working order and replace systems near the end of their useful life. o Insulate water pipes, with a history of freezing or with poor insulation, in locations with frequent extended periods of below freezing temperatures.
13.4 Climate Change Global climate change may affect K–12 facilities in two ways:
Sea level rise will exacerbate flood and tsunami risk for facilities near the coasts of the Pacific Ocean and Puget Sound.
Climate change may alter weather patterns with possible effects on the frequency and severity of storm events and/or droughts.
Sea level rise will increase the importance of flood and/or tsunami mitigation for K–12 facilities at risk as sea levels gradually rise over future decades.
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The effects of climate change on weather patterns are less well understood. However, the impacts on school districts appear likely to be relatively minor.
13.5 Subsidence The term “subsidence” refers to lowering of ground elevations, which may occur gradually over long time periods or very suddenly for several reasons:
Gradual subsidence which typically occurs from ground water pumping or petroleum extraction.
Gradual or sudden subsidence from ground failures in locations of historical underground coal mining.
Sudden subsidence along the Pacific Coast which will occur from a major interface earthquake on the Cascadia Subduction Zone. Subsidence at any given location, which occurs gradually and smoothly over a large area, may be almost imperceptible and have little or no impact on buildings. However, subsidence that is sudden can result in substantial damage to buildings and underground utility lines, especially at soil type boundaries where there may be discontinuities in the extent of subsidence. For schools located on or near the Pacific Ocean coast, subsidence from a M9.0 earthquake on the Cascadia Subduction Zone will range from approximately one meter to three meters, depending on location. This level of subsidence will significantly increase flood risk for school campuses at low elevations near the coast and may result in significant building damage if the extent of subsidence varies across a given campus. This type of subsidence may also result in flooding which could block some evacuation routes for locations subject to tsunamis.
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Appendix One: Scenario Earthquake Results
Earthquake Scenarios: Damage, Casualty Estimates, and Ground Shaking Maps
Table A7.1 Total K–12 Facility Inventory Data by County
County # Schools Building Value ($) Content Value ($) Square Footage Adams 12 $184,456,326 $9,628,620 665,924 Asotin 12 $184,596,050 $9,635,914 662,783 Benton 60 $1,284,835,138 $67,068,394 4,640,203 Chelan 38 $692,619,758 $36,154,751 2,445,687 Clallam 35 $531,000,154 $27,718,208 1,909,804 Clark 130 $2,758,651,359 $144,001,601 9,942,623 Columbia 4 $45,912,069 $2,396,610 160,486 Cowlitz 46 $860,956,310 $44,941,919 3,072,284 Douglas 20 $338,908,317 $17,691,014 1,218,972 Ferry 13 $156,403,070 $8,164,240 556,446 Franklin 28 $578,577,863 $30,201,764 2,145,071 Garfield 2 $31,488,676 $1,643,709 114,209 Grant 54 $820,835,572 $42,847,617 2,954,519 Grays Harbor 44 $722,506,044 $37,714,816 2,608,664 Island 23 $441,648,742 $23,054,064 1,569,389 Jefferson 15 $219,403,276 $11,452,851 797,580 King 558 $11,547,206,129 $602,764,160 41,595,117 Kitsap 82 $1,606,349,301 $83,851,433 5,833,951 Kittitas 19 $332,092,631 $17,335,235 1,188,199 Klickitat 22 $276,113,210 $14,413,110 990,365 Lewis 43 $646,359,277 $33,739,954 2,330,829 Lincoln 16 $213,674,528 $11,153,810 777,735 Mason 21 $340,873,011 $17,793,571 1,204,725 Okanogan 28 $479,167,651 $25,012,551 1,734,336 Pacific 17 $199,587,936 $10,418,490 721,493 Pend Oreille 11 $180,872,803 $9,441,560 642,740 Pierce 270 $5,311,331,698 $277,251,515 19,138,609 San Juan 14 $122,155,021 $6,376,492 439,656 Skagit 48 $853,386,410 $44,546,771 3,134,291 Skamania 10 $137,777,902 $7,192,006 491,851 Snohomish 223 $4,395,178,143 $229,428,299 15,877,108 Spokane 154 $2,986,189,759 $155,879,105 10,629,054 Stevens 44 $599,910,618 $31,315,334 2,146,486 Thurston 78 $1,490,042,702 $77,780,229 5,438,481 Wahkiakum 2 $23,038,082 $1,202,588 80,640 Walla Walla 28 $498,108,503 $26,001,264 1,785,261 Whatcom 72 $1,281,431,256 $66,890,712 4,571,496 Whitman 26 $379,916,326 $19,831,632 1,351,977 Yakima 104 $2,054,877,400 $107,264,600 7,379,684 Total 2,426 $45,808,439,021 $2,391,200,517 164,948,726
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Table A7.2 Cascadia Subduction Zone Intraplate M7.2 Scenario
Minor Major Critical Building Contents County # Schools Max PGA Deaths Building Loss ($) Content Loss ($) BI Loss ($) Total Loss ($) Injuries Injuries Injuries Loss (%) Loss (%) Adams 12 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Asotin 12 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Benton 60 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Chelan 38 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Clallam 35 0.12 1 0 0 0 $1,075,346 0.2% $39,439 0.1% $630,470 $1,745,255 Clark 130 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Columbia 4 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Cowlitz 46 0.16 4 0 0 0 $7,802,332 0.9% $275,184 0.6% $12,452,842 $20,530,357 Douglas 20 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Ferry 13 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Franklin 28 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Garfield 2 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Grant 54 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Grays Harbor 44 0.20 7 1 0 0 $11,635,382 1.6% $413,642 1.1% $17,500,186 $29,549,210 Island 23 0.12 0 0 0 0 $713,106 0.2% $30,426 0.1% $606,459 $1,349,990 Jefferson 15 0.20 1 0 0 0 $1,383,714 0.6% $53,581 0.5% $1,903,648 $3,340,943 King 558 0.24 126 13 1 1 $194,954,844 1.7% $7,292,628 1.2% $290,254,851 $492,502,323 Kitsap 82 0.24 21 2 0 0 $33,124,855 2.1% $1,264,339 1.5% $43,521,276 $77,910,470 Kittitas 19 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Klickitat 22 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Lewis 43 0.24 10 1 0 0 $15,134,058 2.3% $551,953 1.6% $16,692,535 $32,378,546 Lincoln 16 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Mason 21 0.26 7 1 0 0 $10,033,011 2.9% $333,112 1.9% $8,987,246 $19,353,369 Okanogan 28 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Pacific 17 0.16 1 0 0 0 $2,478,899 1.2% $86,040 0.8% $3,631,760 $6,196,698 Pend Oreille 11 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Pierce 270 0.26 108 13 1 2 $149,896,198 2.8% $5,102,167 1.8% $145,579,351 $300,577,716 San Juan 14 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Skagit 48 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Skamania 10 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Snohomish 223 0.16 19 2 0 0 $31,694,523 0.7% $1,292,763 0.6% $34,753,376 $67,740,662 Spokane 154 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Stevens 44 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Thurston 78 0.26 48 7 0 1 $58,207,263 3.9% $1,688,846 2.2% $49,592,683 $109,488,793 Wahkiakum 2 0.08 0 0 0 0 $74,800 0.3% $2,330 0.2% $0 $77,130 Walla Walla 28 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Whatcom 72 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Whitman 26 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Yakima 104 0.00 0 0 0 0 $0 0.0% $0 0.0% $0 $0 Total 2,426 0.26 353 41 2 5 $518,208,330 1.1% $18,426,448 0.8% $626,106,684 $1,162,741,462
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Figure A7.1 Cascadia Subduction Zone Intraplate M7.2 Scenario
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Table A7.3 Seattle Fault System M7.2 Scenario
Building Contents County # Schools Max PGA L1 Injuries L2 Injuries L3 Injuries L4 Deaths Building Loss ($) Content Loss ($) BI Loss ($) Total Loss ($) Loss (%) Loss (%) Adams 12 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Asotin 12 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Benton 60 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Chelan 38 0.06 0.5 0.0 0.0 0.0 $1,020,147 0.1% $37,745 0.1% $0 $1,057,892 Clallam 35 0.08 0.8 0.0 0.0 0.0 $1,380,922 0.3% $51,408 0.2% $0 $1,432,330 Clark 130 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Columbia 4 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Cowlitz 46 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Douglas 20 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Ferry 13 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Franklin 28 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Garfield 2 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Grant 54 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Grays Harbor 44 0.08 0.8 0.1 0.0 0.0 $1,490,671 0.2% $46,931 0.1% $12,424 $1,550,025 Island 23 0.12 0.8 0.1 0.0 0.0 $1,593,624 0.4% $63,632 0.3% $417,118 $2,074,375 Jefferson 15 0.28 1.1 0.1 0.0 0.0 $1,607,675 0.7% $55,281 0.5% $1,349,789 $3,012,746 King 558 0.74 3240.0 811.0 106.9 209.6 $2,240,275,394 19.4% $43,889,526 7.3% $1,913,047,418 $4,197,212,338 Kitsap 82 0.72 650.8 167.0 22.2 43.6 $431,687,467 26.9% $8,515,831 10.2% $391,214,331 $831,417,628 Kittitas 19 0.08 0.1 0.0 0.0 0.0 $313,264 0.1% $13,574 0.1% $0 $326,838 Klickitat 22 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Lewis 43 0.08 0.7 0.1 0.0 0.0 $1,186,395 0.2% $34,983 0.1% $0 $1,221,378 Lincoln 16 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Mason 21 0.52 18.1 3.7 0.4 0.9 $16,006,419 4.7% $357,857 2.0% $14,002,268 $30,366,545 Okanogan 28 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pacific 17 0.06 0.1 0.0 0.0 0.0 $131,269 0.1% $4,544 0.0% $0 $135,813 Pend Oreille 11 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pierce 270 0.28 72.0 8.4 0.5 1.0 $96,539,125 1.8% $2,715,722 1.0% $119,142,253 $218,397,100 San Juan 14 0.06 0.0 0.0 0.0 0.0 $97,952 0.1% $3,966 0.1% $0 $101,918 Skagit 48 0.08 1.2 0.1 0.0 0.0 $1,833,876 0.2% $70,602 0.2% $0 $1,904,479 Skamania 10 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Snohomish 223 0.20 40.8 4.2 0.2 0.4 $56,422,527 1.3% $1,679,314 0.7% $74,823,315 $132,925,156 Spokane 154 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Stevens 44 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Thurston 78 0.12 5.7 0.4 0.0 0.0 $8,746,830 0.6% $326,837 0.4% $4,579,471 $13,653,138 Wahkiakum 2 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Walla Walla 28 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whatcom 72 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whitman 26 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Yakima 104 0.06 0.7 0.0 0.0 0.0 $1,312,126 0.1% $45,392 0.0% $0 $1,357,519 Total 2,426 0.74 4034 995 130 255 $2,861,645,684 6.2% $57,913,146 2.4% $2,518,588,387 $5,438,147,218
Page | 257
Figure A7.2 Seattle Fault System M7.2 Scenario
Page | 258
Table A7.4 Southern Whidbey Fault System M7.4 Scenario
Building Contents County # Schools Max PGA L1 Injuries L2 Injuries L3 Injuries L4 Deaths Building Loss ($) Content Loss ($) BI Loss ($) Total Loss ($) Loss (%) Loss (%) Adams 12 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Asotin 12 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Benton 60 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Chelan 38 0.08 0.1 0.0 0.0 0.0 $127,623 0.0% $4,951 0.0% $0 $132,574 Clallam 35 0.20 6.1 0.8 0.1 0.1 $7,791,448 1.5% $188,510 0.7% $7,328,001 $15,307,959 Clark 130 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Columbia 4 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Cowlitz 46 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Douglas 20 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Ferry 13 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Franklin 28 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Garfield 2 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Grant 54 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Grays Harbor 44 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Island 23 0.70 155.1 40.1 5.4 10.7 $109,072,071 24.7% $2,191,563 9.5% $79,060,373 $190,324,008 Jefferson 15 0.44 30.5 6.8 0.8 1.6 $24,206,918 11.0% $452,834 4.0% $30,338,436 $54,998,187 King 558 0.68 575.8 114.6 13.0 25.4 $532,953,765 4.6% $11,815,480 2.0% $441,657,566 $986,426,812 Kitsap 82 0.24 13.7 1.4 0.1 0.1 $20,323,653 1.3% $649,291 0.8% $23,666,979 $44,639,923 Kittitas 19 0.08 0.0 0.0 0.0 0.0 $76,850 0.0% $3,065 0.0% $0 $79,915 Klickitat 22 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Lewis 43 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Lincoln 16 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Mason 21 0.08 0.3 0.0 0.0 0.0 $628,597 0.2% $24,818 0.1% $0 $653,416 Okanogan 28 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pacific 17 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pend Oreille 11 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pierce 270 0.12 13.5 1.0 0.0 0.0 $21,576,899 0.4% $781,078 0.3% $10,367,124 $32,725,101 San Juan 14 0.20 1.5 0.2 0.0 0.0 $2,184,588 1.8% $64,335 1.0% $2,356,995 $4,605,918 Skagit 48 0.20 12.0 1.4 0.1 0.2 $15,004,691 1.8% $417,230 0.9% $17,302,344 $32,724,265 Skamania 10 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Snohomish 223 0.70 1505.4 382.3 50.1 98.1 $1,009,846,812 23.0% $19,593,773 8.5% $790,928,250 $1,820,368,835 Spokane 154 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Stevens 44 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Thurston 78 0.08 0.4 0.0 0.0 0.0 $594,804 0.0% $23,966 0.0% $0 $618,770 Wahkiakum 2 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Walla Walla 28 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whatcom 72 0.12 3.5 0.2 0.0 0.0 $6,117,349 0.5% $224,337 0.3% $2,054,540 $8,396,226 Whitman 26 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Yakima 104 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Total 2,426 0.70 2318 549 70 136 $1,750,506,069 3.8% $36,435,231 1.5% $1,405,060,608 $3,192,001,908
Page | 259
Figure A7.3 Southern Whidbey Fault System M7.4 Scenario
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Table A7.5 Chelan Fault System M7.2 Scenario
Building Contents County # Schools Max PGA L1 Injuries L2 Injuries L3 Injuries L4 Deaths Building Loss ($) Content Loss ($) BI Loss ($) Total Loss ($) Loss (%) Loss (%) Adams 12 0.06 0.0 0.0 0.0 0.0 $91,443 0.0% $3,152 0.0% $0 $94,595 Asotin 12 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Benton 60 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Chelan 38 0.44 37.3 7.6 0.9 1.8 $40,724,517 5.9% $942,134 2.6% $22,514,073 $64,180,723 Clallam 35 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Clark 130 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Columbia 4 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Cowlitz 46 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Douglas 20 0.64 29.0 7.0 1.0 1.9 $26,408,092 7.8% $738,603 4.2% $18,542,497 $45,689,192 Ferry 13 0.08 0.0 0.0 0.0 0.0 $36,987 0.0% $1,294 0.0% $0 $38,281 Franklin 28 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Garfield 2 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Grant 54 0.12 2.0 0.2 0.0 0.0 $3,368,180 0.4% $104,160 0.2% $4,110,619 $7,582,959 Grays Harbor 44 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Island 23 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Jefferson 15 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 King 558 0.08 0.1 0.0 0.0 0.0 $110,530 0.0% $3,685 0.0% $0 $114,215 Kitsap 82 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Kittitas 19 0.12 0.6 0.0 0.0 0.0 $1,166,719 0.4% $43,178 0.2% $58,151 $1,268,047 Klickitat 22 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Lewis 43 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Lincoln 16 0.08 0.1 0.0 0.0 0.0 $92,705 0.0% $2,708 0.0% $0 $95,413 Mason 21 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Okanogan 28 0.28 6.0 0.9 0.1 0.2 $7,476,635 1.6% $190,274 0.8% $6,978,652 $14,645,561 Pacific 17 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pend Oreille 11 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pierce 270 0.00 0.0 0.0 0.0 0.0 $38,508 0.0% $2,539 0.0% $8,728 $49,775 San Juan 14 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Skagit 48 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Skamania 10 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Snohomish 223 0.00 0.0 0.0 0.0 0.0 $2,909 0.0% $74 0.0% $36,077 $39,060 Spokane 154 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Stevens 44 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Thurston 78 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Wahkiakum 2 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Walla Walla 28 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whatcom 72 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whitman 26 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Yakima 104 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Total 2,426 0.64 75 16 2 4 $79,517,226 0.17% $2,031,801 0.08% $52,248,796 $133,797,823
Page | 261
Figure A7.4 Chelan Fault System M7.2 Scenario
Page | 262
Table A7.6 Cle Elum Seismic Zone M6.8 Scenario
Building Contents County # Schools Max PGA L1 Injuries L2 Injuries L3 Injuries L4 Deaths Building Loss ($) Content Loss ($) BI Loss ($) Total Loss ($) Loss %) Loss (%) Adams 12 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Asotin 12 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Benton 60 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Chelan 38 0.08 0.7 0.0 0.0 0.0 $1,497,402 0.2% $58,165 0.2% $0 $1,555,567 Clallam 35 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Clark 130 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Columbia 4 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Cowlitz 46 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Douglas 20 0.08 0.3 0.0 0.0 0.0 $477,472 0.1% $16,510 0.1% $0 $493,981 Ferry 13 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Franklin 28 0.04 0.0 0.0 0.0 0.0 $0 0.0% $17 0.0% $0 $17 Garfield 2 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Grant 54 0.08 0.5 0.0 0.0 0.0 $865,925 0.1% $26,377 0.1% $0 $892,301 Grays Harbor 44 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Island 23 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Jefferson 15 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 King 558 0.08 0.5 0.0 0.0 0.0 $715,230 0.0% $26,956 0.0% $0 $742,186 Kitsap 82 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Kittitas 19 0.28 9.9 1.4 0.1 0.2 $12,781,133 3.8% $295,157 1.7% $10,342,017 $23,418,307 Klickitat 22 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Lewis 43 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Lincoln 16 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Mason 21 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Okanogan 28 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pacific 17 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pend Oreille 11 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pierce 270 0.08 0.0 0.0 0.0 0.0 $73,470 0.0% $3,914 0.0% $8,728 $86,113 San Juan 14 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Skagit 48 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Skamania 10 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Snohomish 223 0.04 0.0 0.0 0.0 0.0 $2,909 0.0% $74 0.0% $36,077 $39,060 Spokane 154 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Stevens 44 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Thurston 78 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Wahkiakum 2 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Walla Walla 28 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whatcom 72 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whitman 26 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Yakima 104 0.28 15.5 1.9 0.1 0.3 $21,715,709 1.1% $683,617 0.6% $27,621,686 $50,021,013 Total 2,426 0.28 27 4 0 1 $38,129,250 0.08% $1,110,788 0.05% $38,008,508 $77,248,545
Page | 263
Figure A7.5 Cle Elum Seismic Zone M6.8 Scenario
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Table A7.7 Mill Creek Fault Zone M7.0 Scenario
Building Contents Loss Contents County # Schools Max PGA L1 Injuries L2 Injuries L3 Injuries L4 Deaths Building Loss ($) BI Loss ($) Total Loss ($) Loss (%) ($) Loss (%) Adams 12 0.06 0.0 0.0 0.0 0.0 $78,463 0.0% $2,696 0.0% $0 $81,159 Asotin 12 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Benton 60 0.16 2.7 0.2 0.0 0.0 $3,914,352 0.3% $119,328 0.2% $2,838,250 $6,871,930 Chelan 38 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Clallam 35 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Clark 130 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Columbia 4 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Cowlitz 46 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Douglas 20 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Ferry 13 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Franklin 28 0.08 0.7 0.1 0.0 0.0 $842,680 0.1% $22,593 0.1% $130,565 $995,838 Garfield 2 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Grant 54 0.08 0.6 0.0 0.0 0.0 $894,050 0.1% $26,797 0.1% $82,597 $1,003,445 Grays Harbor 44 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Island 23 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Jefferson 15 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 King 558 0.06 0.0 0.0 0.0 0.0 $15,198 0.0% $654 0.0% $0 $15,852 Kitsap 82 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Kittitas 19 0.08 0.4 0.0 0.0 0.0 $838,813 0.3% $33,121 0.2% $0 $871,933 Klickitat 22 0.16 1.2 0.1 0.0 0.0 $1,965,705 0.7% $62,834 0.4% $2,853,880 $4,882,419 Lewis 43 0.06 0.0 0.0 0.0 0.0 $32,901 0.0% $1,049 0.0% $0 $33,949 Lincoln 16 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Mason 21 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Okanogan 28 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pacific 17 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pend Oreille 11 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pierce 270 0.00 0.0 0.0 0.0 0.0 $38,508 0.0% $2,539 0.0% $8,728 $49,775 San Juan 14 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Skagit 48 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Skamania 10 0.06 0.1 0.0 0.0 0.0 $104,538 0.1% $3,107 0.0% $0 $107,645 Snohomish 223 0.00 0.0 0.0 0.0 0.0 $2,909 0.0% $74 0.0% $36,077 $39,060 Spokane 154 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Stevens 44 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Thurston 78 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Wahkiakum 2 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Walla Walla 28 0.06 0.0 0.0 0.0 0.0 $92,234 0.0% $2,551 0.0% $0 $94,786 Whatcom 72 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whitman 26 0.00 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Yakima 104 0.36 54.5 10.0 1.1 2.2 $57,420,091 2.8% $1,664,285 1.6% $50,821,532 $109,905,907 Total 2,426 0.36 60 10 1 2 $66,240,443 0.14% $1,941,627 0.08% $56,771,629 $124,953,698
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Figure A7.6 Mill Creek Fault Zone M7.0 Scenario
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Table A7.8 Latah Fault Zone M5.5 Scenario
Building Contents Loss Contents County # Schools Max PGA L1 Injuries L2 Injuries L3 Injuries L4 Deaths Building Loss ($) BI Loss ($) Total Loss ($) Loss (%) ($) Loss (%) Adams 12 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Asotin 12 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Benton 60 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Chelan 38 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Clallam 35 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Clark 130 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Columbia 4 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Cowlitz 46 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Douglas 20 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Ferry 13 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Franklin 28 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Garfield 2 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Grant 54 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Grays Harbor 44 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Island 23 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Jefferson 15 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 King 558 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Kitsap 82 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Kittitas 19 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Klickitat 22 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Lewis 43 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Lincoln 16 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Mason 21 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Okanogan 28 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pacific 17 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pend Oreille 11 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pierce 270 0.02 0.0 0.0 0.0 0.0 $38,508 0.0% $2,539 0.0% $8,728 $49,775 San Juan 14 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Skagit 48 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Skamania 10 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Snohomish 223 0.02 0.0 0.0 0.0 0.0 $2,909 0.0% $74 0.0% $36,077 $39,060 Spokane 154 0.24 13.9 1.2 0.0 0.1 $29,524,733 1.0% $1,310,012 0.8% $40,826,098 $71,660,842 Stevens 44 0.08 0.0 0.0 0.0 0.0 $113,586 0.0% $4,122 0.0% $0 $117,708 Thurston 78 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Wahkiakum 2 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Walla Walla 28 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whatcom 72 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whitman 26 0.04 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Yakima 104 0.02 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Total 2,426 0.24 14 1 0 0 $29,679,735 0.06% $1,316,763 0.06% $40,870,903 $71,867,402
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Figure A7.7 Latah Fault Zone M5.5 Scenario
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Table A7.9 Hite Fault System M6.8 Scenario
Building Contents County # Schools Max PGA L1 Injuries L2 Injuries L3 Injuries L4 Deaths Building Loss ($) Content Loss ($) BI Loss ($) Total Loss ($) Loss (%) Loss (%) Adams 12 0.08 0.2 0.0 0.0 0.0 $250,052 0.1% $7,365 0.1% $0 $257,417 Asotin 12 0.06 0.2 0.0 0.0 0.0 $290,614 0.2% $8,025 0.1% $0 $298,639 Benton 60 0.08 2.1 0.2 0.0 0.0 $3,635,178 0.3% $114,907 0.2% $0 $3,750,085 Chelan 38 0 0 0 0 0 $677,034 0.1% $26,341 0.1% $0 $703,375 Clallam 35 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Clark 130 0.08 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Columbia 4 0.24 1.7 0.3 0.0 0.1 $2,074,600 4.5% $62,324 2.6% $1,197,225 $3,334,149 Cowlitz 46 0.08 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Douglas 20 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Ferry 13 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Franklin 28 0.12 1.2 0.1 0.0 0.0 $1,661,797 0.3% $51,464 0.2% $13,219 $1,726,480 Garfield 2 0.08 0.1 0.0 0.0 0.0 $155,015 0.5% $4,476 0.3% $0 $159,491 Grant 54 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Grays Harbor 44 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Island 23 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Jefferson 15 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 King 558 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Kitsap 82 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Kittitas 19 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Klickitat 22 0.08 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Lewis 43 0.08 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Lincoln 16 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Mason 21 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Okanogan 28 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pacific 17 0.08 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pend Oreille 11 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Pierce 270 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 San Juan 14 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Skagit 48 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Skamania 10 0.08 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Snohomish 223 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Spokane 154 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Stevens 44 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Thurston 78 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Wahkiakum 2 0.08 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Walla Walla 28 0.48 78.8 20.6 3.1 6.2 $53,054,897 10.7% $1,373,707 5.3% $30,218,103 $84,646,707 Whatcom 72 0.06 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Whitman 26 0.08 0.3 0.0 0.0 0.0 $588,848 0.2% $16,689 0.1% $0 $605,537 Yakima 104 0.08 0.0 0.0 0.0 0.0 $0 0.0% $0 0.0% $0 $0 Total 2,426 0.48 85 21 3 6 $62,388,034 0.14% $1,665,298 0.07% $31,428,547 $95,481,879
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Figure A7.8 Hite Fault System M6.8 Scenario
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Appendix Two: References
Chapter Seven: Earthquakes 1. United States Geological Survey (2013). Largest Earthquakes in the World Since 1900. http://earthquake.usgs.gov/earthquakes/world/10_largest_world.php 2. University of Washington (2002). Map and List of Significant Quakes in WA and OR, The Pacific Northwest Seismograph Network. University of Washington Department of Earth Sciences. 3. Washington State Department of Natural Resources (2013). http://fortress.wa.gov/dnr/app1/dataweb/dmmatrix.html 4. Cascadia Region Earthquake Working Group (2005): Cascadia Subduction Zone Earthquakes: A Magnitude 9.0 Earthquake Scenario. 5. Oregon Seismic Safety Policy Advisory Commission (2013). The Oregon Resilience Plan. 6. United States Geological Survey (2013). http://earthquake.usgs.gov/hazards/qfaults/map/ 7. United States Geological Survey (2013). http://earthquake.usgs.gov/hazards/qfaults/map/ 8. United States Geological Survey (2013). http://earthquake.usgs.gov/hazards/qfaults/map/ 9. Goldfinger and Others (2012), Turbidite Event History: Methods and Implications for Holocene Paleoseismicity of the Cascadia Subduction Zone, United States Geological Survey, Professional Paper 1661-F. 10. King, Philip G., Aaron R. McGregor and Justin D. Whittet (2011). The Economic Costs of Sea-Level Rise to California Beach Communities, California Department of Boating and Waterways. 11. Washington State Department of Natural Resources (2013). Modeling A Magnitude 7.2 Earthquake on the Seattle Fault Zone in Central Puget Sound.
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Chapter 8: Tsunamis 1. Intergovernmental Oceanographic Commission, 2007. Tsunami, The Great Waves, Revised Edition. Paris, UNESCO, IOC Brochure 2008-1. 2. United States Geological Survey, 2005. Surviving a Tsunami – Lessons Learned from Chile, Hawaii, and Japan. Circular 1187. 3. Tsunami photo, Tohoku, Japan, 2011. Source unknown.
4. Oregon Department of Geology and Mineral Industries, 2007. Tsunami Hazards in Oregon. 5. Paine, Michael P. (1999). Asteroid Impacts: The Extra Hazard Due to Tsunami. Science of Tsunami Hazards, Volume 17, pp. 155-166. 6. Near Earth Object, Wikipedia article which references the technical asteroid literature: http://en.wikipedia.org/wiki/Near-Earth_object 7. Crawford, David A. and Charles L. Mader (1998). Modeling Asteroid Impact and Tsunami. Science of Tsunami Hazards, Volume 16, pp. 21-30. 8. Goldfinger, C., and Others, 2011. Turbidite Event History: Methods and Implications for Holocene Paleoseismicity of the Cascadia Subduction Zone. U.S. Geological Survey Professional Paper 1661-F. 9. Washington State Enhanced Hazard Mitigation Plan, 2010. Section 5.8, Hazard Profile – Tsunami. 10. King, Philip G., Aaron R. McGregor and Justin D. Whittet (2011). The Economic Costs of Sea-Level Rise to California Beach Communities, California Department of Boating and Waterways.
Chapter 9: Volcanic Hazards 1. Smithsonian Institution, Global Volcanism Project: http://volcano.si.edu/world/region/.cfm?rnum=1201 2. United States Geological Survey, Volcanic Hazards Program: http://volcanoes.usgs.gov/observatories/cvo/ 3. United States Geological Survey, Digital data set of volcano hazards for active Cascade Volcanoes, Washington – Schilling, S.P., 1996, USGS Open-File Report 96-178. 4. United States Geological Survey, Digital data for volcano hazards from Mount Rainier, Washington, Revised 1998 – Schilling, et.al, 2008, USGS Open-File Report 2007-1220.
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5. United States Geological Survey, Volcano Hazards from Mount Rainier, Washington, Revised 1998 – Hoblitt, et.al. 1998, USGS Open-File Report 98-428. 6. United States Geological Survey, Potential Volcanic Hazards from Future Activity at Mount Baker, Washington – Gardner, et.al. 1995, USGS Open-File Report 95-498. 7. United States Geological Survey, Volcanic-Hazard Zonation for Glacier Peak Volcano, Washington – Waitt, et.al., 1995, USGS Open-File Report 95-499. 8. United States Geological Survey, Volcano Hazards in the Mount Adams Region, Washington – Scott, et.al., 1995, USGS Open-File Report 95-492. 9. United States Geological Survey, Volcanic-Hazard Zonation for Mount St. Helens, Washington – Wolfe and Pierson, 1995, USGS Open-File Report 95-497. 10. United States Geological Survey, Volcano Hazards in the Mount Hood Region, Oregon – Scott, et.al. 1997, USGS Open-File Report 97-89. 11. United States Geological Survey, Digital data for volcano hazards of the Mount Hood Region, Oregon – Schilling, et.al, 2008, USGS Open-File Report 2007-1222. 12. United States Geological Survey: http://volcanoes/usgs.gov/activity/alertsystem/index.php 13. United States Geological Survey: http://volcanoes/usgs.gov/volcanoes/mount_rainier_monitoring_99.html
Chapter 10: Floods 1. Photo credit: Steve Ringman, The Seattle Times.
2. Philip King, Aaron McGregor and Justin Whittet (2011), The Economic Costs of Sea-Level Rise to California Beach Communities. California Department of Boating and Waterways and San Francisco State University. 3. Washington Emergency Management Division records.
4. MGS Engineering and Oregon Climate Service (2006), Washington 100-Year 24-Hour Precipitation. 5. FEMA 480: National Flood Insurance Program, Floodplain Management Requirements, A Study Guide and Desk Reference for Local Officials. Available in hard copy and on CD from FEMA at: (800) 480-2520. 6. Washington Department of Ecology (2013), Inventory of Dams in the State of Washington. 7. Washington Department of Ecology (2011), 2010 Report to the Legislature: Status of High and Significant Hazard Dams in Washington with Safety Deficiencies. 8. Columbia River Basin dam map, source unknown.
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Chapter 11: Wildland/Urban Interface Fires 1. 2013 Washington State Enhanced Hazard Mitigation Plan, Section 5.5, Hazard Profile – Wildland Fire and Urban Fire (December 2012, Draft). 2. Northwest Interagency Coordination Center, Northwest Annual Fire Report 2011, March 26, 2012. 3. National Fire Protection Association, Brush, Grass and Forest Fires, August 2010.
4. Washington Department of Natural Resources, Fire Risk Map, 2011.
5. USGS Landfire Map. http://landfire.cr.usgs.gov/viewer/
Chapter 12: Landslides 1. United States Geological Survey (2004), Landslide Types and Processes, Fact Sheet 2004-3072. 2. Washington State Military Department, Emergency Management Division (2009), Hazard Identification and Vulnerability Assessment (HIVA). 3. Washington State Enhanced Hazard Mitigation Plan, Section 5.6, Hazard Profile – Landslide, October 2010. 4. Washington Department of Natural Resources: http://wigm.dnr.wa.gov/ 5. Washington Department of Natural Resources (2011), unpublished map: Slope Stability Model for Shallow Landslide Potential, West and East Side.
Chapter 13: Other Hazards 1. Washington State Enhanced Hazard Mitigation Plan (2013). Washington State Military Department, Emergency Management Division.
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