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2025 Hazard Mitigation Plan <br />Kittitas County, Washington <br /> <br /> <br />Chapter 4: Hazard Identification and Risk Assessment 72 <br />and meteorologists analyze snow observations from across the area and weather forecast guidance to <br />create a forecast specific to each zone. <br /> <br />On a daily basis, avalanche and snowpack information comes in from NWAC forecasters and <br />professional observers, avalanche professionals, backcountry travelers, and remote weather stations <br />from around the region. Professional ski patrols, highway avalanche control programs, national park and <br />forest rangers, ski guides, and other professionals share information with NWAC throughout the winter <br />season in order to ensure that the best and most pertinent information becomes incorporated into the <br />forecasts.59F <br />60 <br /> <br />The North American Public Avalanche Danger Scale (NAPADS) is a system that rates avalanche danger <br />and provides general travel advice based on the likelihood, size, and distribution of expected avalanches. <br />It consists of five (5) levels, from least to highest amount of danger – low (1), moderate (2), considerable <br />(3), high (4), extreme (5). Danger ratings are typically provided for three (3) distinct elevation bands. <br />Although the danger ratings are assigned in numerical levels, the danger increases exponentially <br />between levels. In other words, the hazard rises more dramatically as it ascends toward higher levels on <br />the scale. Table 4-23 lists and describes the five (5) levels of the NWAC Danger Scale.60F <br />61 <br />Table 4-23. North American Public Avalanche Danger Scale <br />Scale Travel Advice Likelihood Size and Distribution <br /> Low (1) <br />Generally safe avalanche <br />conditions. Watch for <br />unstable snow on isolated <br />terrain features. <br />Natural and human- <br />triggered avalanches <br />unlikely. <br />Small avalanches in <br />isolated areas or extreme <br />terrain. <br /> Moderate (2) <br />Heightened avalanche <br />conditions on specific <br />terrain features. Evaluate <br />snow and terrain carefully; <br />identify features of concern. <br />Natural avalanches <br />unlikely; human-triggered <br />avalanches possible. <br />Small avalanches in <br />specific areas; or large <br />avalanches in isolated <br />areas. <br /> Considerable (3) <br />Dangerous avalanche <br />conditions. Careful snowpack <br />evaluation, cautious route- <br />finding and conservative <br />decision-making essential. <br />Natural avalanches <br />possible; human- <br />triggered avalanches <br />likely. <br />Small avalanches in <br />many areas; or large <br />avalanches in specific <br />areas; or very large <br />avalanches in isolated <br />areas. <br /> High (4) <br />Very dangerous avalanche <br />conditions. Travel in <br />avalanche terrain not <br />recommended. <br />Natural avalanches likely; <br />human-triggered <br />avalanches very likely. <br />Large avalanches in <br />many areas; or very large <br />avalanches in specific <br />areas. <br /> Extreme (5) <br />Extraordinarily dangerous <br />avalanche conditions. Avoid <br />all avalanche terrain. <br />Natural and human- <br />triggered avalanches <br />certain. <br />Very large avalanches in <br />many areas. <br /> <br />NWAC partners with the National Weather Service (NWS) to help disseminate avalanche advisories to <br />the general public. Table 4-24 lists and describes the different types of NWAC avalanche advisories.61F <br />62 <br /> <br /> <br />60 Northwest Avalanche Center. (n.d.). About Forecasts. Retrieved from https://nwac.us/about-the-forecasts-2/. <br />61 Northwest Avalanche Center. (n.d.). North American Public Avalanche Danger Scale. Retrieved from <br />https://avalanche.org/avalanche-encyclopedia/human/resources/north-american-public-avalanche-danger-scale/. <br />62 Northwest Avalanche Center. (n.d.). About Forecasts. Retrieved from https://nwac.us/about-the-forecasts-2/.