Hazard Ldentification &
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Kitsap County Multi-Hazard Mitigation Plan (MHMP) 2019 Table of Gontents lntroduction .1 Gounty & Gity Profiles .2 Kitsap County....... ..3 Bainbridge lsland 26 Bremerton 3B Port Orchard ............... 38 Poulsbo 54 Natural Hazards 62 Droughts 64 Earthquakes................ 70 Floods 70 Forest & Urban Fires.......... ..86 Landslides & Erosion 106 Severe Storms/Tornadoes 116 Tsunamis, High Waves, & Seiches ............... 122 Volcanic Ash Fall..... 132 Technological Hazards & Human-Caused Threats... 136 Cybersecurity.............. 138 Dam Fai1ure ............... 140 Energy Emergency 144 Hazardous Sites/Materials ............ 148 Radiological Emergencies............. ,154 Search & Rescue Emergencies................ 156 Terrorism 158 Transportation Mass Casualty lncident 160 Epidemics (Human & Animal)... .164 References & Authorities 172 Kitsap County Multi-Hazard Mitigation Plan (MHMP) 2019 ii Tables & Figures Table 1: Definitions ............... ...........2 Table 2: HIVA 2019 Ratin9s................ ............... 5 Table 3: Risk Rating Adjective Descriptions............... .......... 8 Table 4: Kitsap County Most Recent Population Estimates ....................4 Table 5: Civilian Labor Force, 2017 Estimates (US Census) ..................7 Table 6: Nonfarm lndustry Employment................ ...............7 Table 7: School District Attendance,20lO Estimates (US Census).............. .,..........7 Table 8: lndian Nations, 2019 Esri Demographics............. .....................7 Table 9: Kitsap County Areas of Mitigation lnterest...... ........ 8 Table 10: Kitsap County Housing Characteristics 2013-2017 American Community Survey 5- Year Estimates (US Census...... ....... I Table 11: Transportation Links in Kitsap County .................12 Table 12. Kitsap County Critical Facilities & Cultural Resources ...........15 Table 13: Kitsap County Emergency/Disaster History 1962-2019............... ............24 Table 14: Kitsap County Hazard Losses'1960-2017 ............... ..............24 Table 15: Bainbridge lsland Population lnformation ............26 Table 16: Bainbridge lsland Vulnerable Population .............27 Table 17: City of Bainbridge Areas of Mitigation lnterest..... ..................29 Table 18: Bainbridge lsland Housing Characteristics 2013-2017 American Community Survey 5- Year Estimates (US Census) ..........30 Table 19: Bainbridge lsland Critical Facilities ......................34 Table 20: Emergency/Disaster History for Bainbridge lsland... ..............36 Table 21 : Bremerton Population lnformation ............. Table 22: Populalion Density Bremerton ...........38 Table 23: Bremerton Vulnerable Population............. ...........39 Table 24: City of Bremerton Areas of Mitigation lnterest .....40 Table 25: Bremerton Housing Characteristics 2013-2017 American Community Survey S-Year Estimates (US Census,2017) .........41 Table 26: Emergency/Disaster History for Bremerton.............. ..............44 Table 27: Port Orchard Population lnformation ...................46 Table 28: City of Port Orchard Areas of Mitigation lnterest...... .......... ...49 Table 29: Port Orchard Housing Characteristics 2013-2017 American Community Survey 5- Year Estimates (US Census, 2017)......... ..........49 Table 30: Emergency/Disaster History for Port Orchard ......53 Table 31: Poulsbo Population lnformation .........54 Table 32: City of Poulsbo Areas of Mitigation lnterest .........57 Table 33: Poulsbo Housing Characteristics 2013-2017 American Community Survey 5-Year Estimates (US Census,2o17) .........58 Table 34: Emergency/Disaster History for Poulsbo .............61 Table 35: Building Stock and Critical Facilities by Jurisdiction Affected by Drought...................65 Table 36: Drought Severity Classification................ ............65 Table 37: Comparison of Earthquake Measurements............. ...,...........78 Table 38: Hazus Earthquake Resultsfora SeattleMT.2 Earthquake .....................80 Kitsap County Multi-Hazard Mitigation Plan (MHMP) 2019 Table 39: Pre-Code versus Moderate Code Building in Kitsap County.... ................81 Table 40: Washington State Earthquakes............... ...........83 Table 41: Special Flood Hazard Area Assessment ................ .................87 Table 42: Special Flood Hazard Area Assessments............... ................92 Table 43: Community Flooding Characteristics ...................93 Table 44: Community FIRM lnformation ............95 Table 45: Flood Risk Community Characteristics ................97 Table 46: Population by Jurisdiction Affected by Fire in Kitsap County (2012) ......102 Table 47: Building Stock and Critical Facilities by Jurisdiction Affected by Fire .,...102 Table 48: Building Exposure to Lands1ides................ ........108 Table 49: Kitsap County LIDAR Defined Landslides (2012) ................108 Table 50: Building Exposure to Lands1ides................ ........109 Table 51: Fujita Tornado lntensity Scale .........118 Table 52: Building Stock and Critical Facilities by Jurisdiction Affected by Severe Storms......118 Table 53: Building Stock and Critical Facilities by Jurisdiction Affected by Tsunami................125 Table 54: Kitsap County Dams......... ...............141 Table 55: Kitsap County Cleanup & Superfund Sites ........148 Table 56: Closed & Abandoned Landfills in Kitsap County...... ............'150 Table 57: Closed & Abandoned Landfills in Kitsap County...... ............150 Figure 1: Risk Elements ................... 1 Figure 2: Steps to Conduct a Risk Assessment................. ..................... 1 Figure 3: Map of Kitsap County, Kitsap Economic Development Alliance.. ...............2 Figure 4: Map of Census Urbanized Areas & Urban Growth .................. 5 Figure 5: Kitsap County Population Distribution ....................... 6 Figure 6: Kitsap County Populations with Functionaland Access Needs Estimates (2019)........ 6 Figure 7: Comprehensive Land Use Map (2018).............. .....................10 Figure 10: Kitsap County Critical Areas........ .......................13 Figure 9: Map of Culturally Sensitive Sites Port Madison lndian Reservation ..........17 Figure 10: CriticalAreas of Kitsap County....... ....................21 Figure 11: Age Distribution ..............27 Figure 12: Bainbridge lsland Population Density, @ OpenStreetMap Contributors....................28 Figure 13: Topography of Bainbridge 1s1and......... ...............35 Figure 14: Population Distribution........... ..........38 Figure 15: Bremerton Population Density, @ OpenStreetMap Contributors............... .. .... ....40 Figure 16: Topographical Feature, City of Bremerton. .........43 Figure 17: Population Distribution........... ..,.......46 Figure 18: South Kitsap Vulnerable Population ...................47 Figure 55: Population Density: Port Orchard.............. .........47 Figure 20: Port Orchard Population Density ......47 Figure 21: Elevation (L|DAR): Port Orchard ............... .........51 Figure 22: Poulsbo Population Distribution ........54 Figure 23: North Kitsap Vulnerable Population. ...................55 Figure 24: Population Density: City of Poulsbo..... ...............56 Figure 25: Poulsbo Elevation using L|DAR ........60 Figure 26: Puget Sound Faults........ ..................70 Kitsap County Multi-Hazard Mitigation Plan (MHMP) 2019 IV Figure 27: Building Damage Percent during a7.2M Earthquake on the Seattle Fault ........ ..74 Figure 16: Seismic Hazards ..77 Figure 29: Seismic Hazards ..77 Figure 30: Shaking lntensity for a7.2 Seattle Fault Earthquake.......... ..79 Figure 31: Historical Earthquake Damage ..83 Figure 32: Frequency of Damaging Earthquake Shaking Around the US ..84 Figure 33: 1% Annual Chance Depth Grid (in feet) for the City of Bremerton Area............. ..88 Figure 34: BFE Plus 1-, 2-, and 3-Foot Grids for the City of Bremerton Area ..88 Figure 35: FEMA Flood Zone Designation ..90 Figure 36: Watercourse and Surface Water ..91 Figure 37: NFIP FIRMS Panel Map........... ..94 Figure 38: Federal Fire Occurrence Map 1980-2016 (USGS) 100 Figure 39: Shallow Landslide Susceptibility Zones and Building lmpacts 107 Figure 40: Landslide Hazard Map.......... 110 Figure 41: Erosion Hazard Map .......... 111 Figure 42: Porl Orchard 2018 Tornado Path 116 Figure 43: Maximum lnundation Depths for the Tsunami Generated by the Seattle Fault Scenario.... 't23 Figure 44: PotentialTsunami lnundation Zone showing the Cities of Bremerton and Port Orchard (Kitsap County GIS 201 1 )............... 123 Figure 45: Types of Tsunami Risk (WADNR) ........... 125 Figure 27: How tsunamis are created along the Cascadia subduction zone.......... 126 Figure 47: Schematic diagram of the sequence of events in a Cascadia Subduction Zone earthquake '126 Figure 48: Tsunamis in Washington.......... 128 Figure 49: Volcano Hazards.... 132 Kitsap County Multi-Hazard Mitigation Plan (MHMP) 2019 V lntroduction Rlsk, for hazard mitigation planning, is the potentialfor damage, loss, or other impacts created by the interaction of natural hazards with community assets. The exposure of people, property, and other community assets to natural hazards can result in disasters depending on the consequential impacts of those hazards. Hazards may include droughts, earthquakes, floods, forest fires, landslides, severe storms, tsunamis, and volcanic ash fall. The type and severity of impacts are based on the extent of the hazard and the vulnerability of the asset, as