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4.2.3.1 Likelihood The model output which best represents wildfire likelihood in Kittitas County is the burn probability output from the FSim modeling done for the Pacific Northwest Region (Oregon and Washington boundaries) risk assessment. It represents a true annual burn probability that considers all possible weather scenarios. This provides a long-term perspective on the relative likelihood of fire for any location in the county in any given year. To produce a map of relative likelihood for the county, the average burn probability for each catchment was calculated, and those averages were classified into four classes of low, moderate, high, and very high. The classes are relative to the distribution of catchment averages only within Kittitas County and are based on quartiles. Therefore, the high and very high classes represent all catchments with an average burn probability value above the county median. The average burn probabilities for watersheds range from 0 to 0.025, with a mean of 0.01. This means, on average, any specific location (i.e., 180 -meter pixel) has about a 1 in 100 chance of burning in any given year. 4.2.3.2 Susceptibility and Risk Information about susceptibility (or vulnerability) of specific assets is more difficult to map. Neither the Pyrologix nor the PNRS work in Kittitas County provides enough information to adequately represent the susceptibility of communities to wildfire. While the Pyrologix analysis included some datasets that could address community -level susceptibility (e.g., distance to roads, fire stations, water sources, golf courses, etc.), their assessment did not integrate this information with likelihood and intensity data into standard, accepted metrics of risk. The PNRS analysis for the Pacific Northwest Region Quantitative Risk Assessment report did develop abstract estimates of susceptibility (known as response functions) for a variety of natural resources and built assets, but the focus of that assessment was on setting land management and wildfire management priorities on national forest lands. The response function for communities developed in that analysis estimated negative impacts to communities at all levels of fire intensity, but these impacts are vaguely defined and not specific for different types of structures. While information from both assessments provides some insights into wildfire risk, neither facilitates a thorough mapping of risk across the county. Moving forward, susceptibility could be evaluated at multiple scales to facilitate calculation of wildfire risk metrics in and around developed areas in the county. At a community or neighborhood scale, factors similar to those used in the Pyrologix assessment could be used to develop community -level susceptibility ratings. The rating areas could be watersheds, like the catchments used here, but may be more meaningful if they represent specific community or neighborhood boundaries used for planning and fire response purposes. Within each rating area, factors such as ingress/egress, distance to nearest fire station (or average response time), local water supply (e.g., streams, lakes, cisterns), and structure density could inform integrated ratings of community susceptibility to wildfire of different intensities. Community Wildfire Protection Plan 34 September 2018