Resolution_2025 Kittitas County Hazard Mitigation Plan

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2025 Hazard Mitigation Plan Kittitas County, Washington Chapter 4: Hazard Identification and Risk Assessment 210 Table 4-163. Winter Weather Risk Index (FEMA National Risk Index) Jurisdiction Rating Score Kittitas County Relatively Low 35.7 Risk Index scores are calculated using an equation that combines scores for Expected Annual Loss due to natural hazards, Soci al Vulnerability and Community Resilience (Expected Annual Loss x Social Vulnerability / Community Resilience = Risk Index). The ice storm Risk Index score and rating represent a community's relative risk for ice storm when compared to the rest of the United States. Table 4-164 illustrates the ice storm Risk Index rating and score for Kittitas County. Table 4-164. Ice Storm Risk Index (FEMA National Risk Index) Jurisdiction Rating Score Kittitas County Very Low 2.0 Risk Index scores are calculated using an equation that combines scores for Expected Annual Loss due to natural hazards, Soci al Vulnerability and Community Resilience (Expected Annual Loss x Social Vulnerability / Community Resilience = Risk Index). Table 4-165 represents the Winter Weather Total Risk Score for the Kittitas County, based on the Risk Assessment Methodology, as defined in Section 4.3 of this Plan. Table 4-165. Winter Weather Total Risk Score Hazard Event Probability Consequence Total Risk Probability Factor Extent Vulnerability Impact Consequence Score Total Risk Score* Winter Weather 3 15 16 24 55 77 Consequence: Sum of all weighted factors. Extent: Sum of the weighted Extent factors. Vulnerability: Sum of the weighted Vulnerability factors. Impact: Sum of the weighted Impact factors. Total Risk Score = Probability x Consequence * Normalized to 100 Total Risk Score Legend Classification Probability Factor Extent Vulnerability Impact Consequence Score Total Risk Score Low (L) 1 0 – 6 0 – 6 0 – 12 0 – 24 0 – 24 Medium (M) 2 7 – 12 7 – 12 13 – 26 25 – 50 25 – 52 High (H) 3 13 – 18 13 – 18 27 – 39 51 – 75 53 and above The legend—specifically the assignment of low, medium, and high—provides an additional means to qualitatively assess the probability factor, sum of weighted factors, and the total risk scores for each hazard. The Consequence Score represents the sum of the Extent, Vulnerability, and Impact Factors. The Total Risk Score is a measure of Probability and Consequence.