Regional Multi-Hazard Mitigation Plan Section 4: Risk Assessment Section 4: Hazard Identification and Risk Assessment List of Tables Table 4.1: Cascading Hazards Resulting from Disasters............................................................................ 185 Table 4.2: Cass County Hazard Summary.................................................................................................. 186 Table 4.3: Cass County Hazard Summary.................................................................................................. 187 Table 4.4: Clay County Hazard Summary .................................................................................................. 188 Table 4.5: Jackson County Hazard Summary ............................................................................................ 189 Table 4.6: Platte County Hazard Summary ............................................................................................... 190 Table 4.7: Ray County Hazard Summary ................................................................................................... 191 List of Hazards Section 4.6 Tornadoes ............................................................................................................................194 Section 4.7 Severe Thunderstorms .........................................................................................................210 Section 4.8 Severe Winter Weather .......................................................................................................223 Section 4.9 Flooding ................................................................................................................................234 Section 4.10 Levee Failures .....................................................................................................................252 Section 4.11 Dam Failures .......................................................................................................................266 Section 4.12 Drought ..............................................................................................................................279 Section 4.13 Heat Waves ........................................................................................................................300 List of Attachments Section 4.14 Attachments .......................................................................................................................311 Attachment 4.1: Summary Assessment of Risk (Cass, Clay, Jackson, Platte and Ray Counties ..............311 Mid-America Regional Council 4.182 June 2020 Regional Multi-Hazard Mitigation Plan Section 4: Risk Assessment Section 4: Hazard Identification and Risk Assessment Requirement The plan shall include a risk assessment that provides the factual basis for activities §201.6(c)(2): proposed in the strategy to reduce losses from identified hazards. Local risk assessments must provide sufficient information to enable the jurisdiction to identify and prioritize appropriate mitigation actions to reduce losses from identified hazards. 4.1 Overview and Changes from 2015 Plan For the 2020 Plan Update, the Planning Team focused on five natural hazards in the region, a decrease from the 18 previous hazards in the 2015 Plan. The selected hazards are consolidated into five main categories: tornadoes, severe thunderstorms, severe winter weather, heat, and flooding. The heat category includes a profile on drought and heat waves. The flooding category includes a profile on flooding, levee failures, and dam failures. Focusing the Plan on natural disasters was done to narrow each jurisdiction’s focus and simplify the selection of, and implementation for, mitigation efforts. The identification of these priority natural hazards was made by the project steering committee, after seeking input from stakeholders at the April 2, 2019, plan kickoff meeting. The statistical risk assessment, used to show maximum and minimum loss estimates, has been removed from all hazard profiles due to complicated calculations and its inability to assist in mitigation planning efforts. Due to this change, the hazard profile sections have been reformatted from the 2015 Plan. Each hazard profile includes: • Description • Historical Occurrences • Probable Location o Magnitude • Impact • Probability of Future Occurrence • Extent o Probable Duration • Vulnerability Analysis • Problem Statements Each profile may differ slightly due to the characteristics of the hazard. The areas that may be affected by weather-related natural hazards are very difficult to identify. Where possible, the locations or geographic areas that may be affected are mapped. Tornadoes, for example, may affect any part of the Kansas City metropolitan area. Severe thunderstorms, severe winter weather, drought, and heat waves are usually widespread weather events that affect parts of the region or the entire region. In the Probable Locations section of each hazard profile, a magnitude rating was given to the five-county area estimating the percent of a county that could be affected during a hazard event. The methodology is explained in Section 4.2. Mid-America Regional Council 4.183 June 2020 Regional Multi-Hazard Mitigation Plan Section 4: Risk Assessment Certain locations — because of specific characteristics of the built environment, socio-economic conditions or a combination of these elements — may be more susceptible to these natural hazards. The Vulnerability Analysis in Section 4.5 highlights these areas and populations. Many sources were researched for data and information relating to hazards in the Kansas City metropolitan area. Principal sources of all-hazard information include FEMA and SEMA. The National Climate Data Center (NCDC), National Oceanic and Atmospheric Administration (NOAA) and the National Weather Service (NWS) were primary sources of information and statistics on weather and/or climate- related hazards. Hazard-specific databases were also researched for this Plan. For instance, the National Drought Mitigation Center at University Nebraska Lincoln was used for the drought profile. The primary sources of information on dams and dam safety were the Missouri Department of Natural Resources (MDNR) Dam Safety Division and the U.S. Army Corps of Engineers’ (USACE) National Inventory of Dams (NID). The primary source for information on levees was the National Levee Database. Other sources of information include MARC Research Services Department; city and county Web sites and officials; existing county, regional and state plans, reports and documents; newspaper and news organization Web sites, articles and accounts of natural disasters; other state and federal agencies, such as the U.S. Census Bureau and Missouri Census Data Center (MCDC); and colleges and universities, especially the University of Missouri and University of Missouri Extension. References are noted at the end of each hazard profile with a bibliography of research sources in Appendix C: Maps and References. Several data deficiencies noted in the 2015 Plan have been corrected or new sources of information identified. These are noted where applicable. 4.1.1 Hazards Not Included and Reasons for Elimination While the Plan was consolidated to only include natural hazards, there are two natural hazards that were removed from the Plan. Wildland fires and earthquakes are not included in this Plan due to low probabilities. In the 2015 Plan, earthquakes rated ‘low’ in all modified Mercalli levels for future probable severity. From 2002-2015, the maximum percentage of any portion of any county affected by wildfires, was 7.5 percent. The majority of every county in the planning area was 0%-1% affected by wildland fires. All man-made hazards were removed from this Plan to help jurisdictions narrow their mitigation efforts. The following hazards may be of concern to one or more local jurisdictions but were not included in the 2020 plan: emerging infectious disease, transboundary animal disease, hazardous materials incidents, mass transportation accidents, cyber disruption, public mass shooter incidents, civil disorder, and terrorism. 4.2 Community-Driven Risk Assessment As part of the 2020 Plan Community Profile Survey, each jurisdiction was asked to re-assess its risks for the natural hazards identified in the Plan. “Cascading hazards,” those hazards resulting from a natural disaster, were listed to be taken into account when re-assessing risk. Table 4.1 shows the relationship between the region’s identified disasters and categories of possible cascading hazards. Any of these Mid-America Regional Council 4.184 June 2020 Regional Multi-Hazard Mitigation Plan Section 4: Risk Assessment cascading hazards alone or in combination with the direct adverse effects of a disaster can potentially impact emergency response operations in affected communities. Table 4.1: Cascading Hazards Resulting from Disasters d/or Loss of Communications Interruption Water Supply Interruption Business Interruption Computer Failure an Records Transportation Interruption Health and/or Environmental Hazards Natural Disaster Power and Tornadoes X X X X X X Severe Thunderstorms X X X Severe Winter Weather X X X X X X Drought X X X Heat Waves X X X Floods X X X X X X Levee Failures X X X X X X Dam Failures X X X X X X X = 50 percent or greater chance of cascading effect resulting from disaster As each county noted the risk each hazard poses to their governance, hazards were re-prioritized or deleted. If a hazard was not of concern, the