2019_KittitasCountyHMP_Volume 1_For Adoption

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CHAPTER 6. IDENTIFIED HAZARDS OF CONCERN AND RISK ASSESSMENT METHODOLOGY 6-5 with geographic hazard data to identify structures exposed to dam failure, landslide, severe weather, volcano, and wildfire. Local information was gathered from a variety of sources. Frequency and severity indicators include past events and the expert opinions of geologists, emergency management specialists and others. The primary data source was the Kittitas County GIS database, augmented with state and federal data sets. Additional data sources for specific hazards were as follows: • Dam Failure—Dam failure inundation data was provided by Kittitas County. • Landslide— Kittitas County provided Washington Department of Natural Resources landslide compilation data. • Severe Weather—Severe weather data was downloaded from the Natural Resources Conservation Service and the National Centers for Environmental Information (NCEI). • Volcano—Volcanic hazard data was obtained from the USGS Cascade Volcano Observatory. • Wildfire—Wildfire data was provided by Kittitas County. 6.4.3 Drought and Avalanche The risk assessment methodologies used for this plan focus on damage to structures. Because drought does not impact structures, the risk assessment for drought was more limited and qualitative than the assessment for the other hazards of concern. Similarly, the avalanche hazard was found to be minimal in developed areas, so the risk assessment for that hazard also was limited and qualitative. 6.4.4 Limitations Loss estimates, exposure assessments and hazard-specific vulnerability evaluations rely on the best available data and methodologies. Uncertainties are inherent in any loss estimation methodology and arise in part from incomplete scientific knowledge concerning natural hazards and their effects on the built environment. Uncertainties also result from the following: • Approximations and simplifications necessary to conduct a study • Incomplete or outdated inventory, demographic or economic parameter data • The unique nature, geographic extent and severity of each hazard • Mitigation measures already employed • The amount of advance notice residents have to prepare for a specific hazard event. These factors can affect loss estimates by a factor of two or more. Therefore, potential exposure and loss estimates are approximate. The results do not predict precise results and should be used only to understand relative risk. Over the long term, Kittitas County and its planning partners will collect additional data to assist in estimating potential losses associated with other hazards.