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CHAPTER 7. AVALANCHE <br />7-6 <br />avalanche activity was delayed or did not occur. Nonetheless an avalanche can occur with little or no <br />warning time, which makes them particularly deadly. <br />During the avalanche season, the Northwest Avalanche Center issues twice daily mountain weather <br />forecasts and daily avalanche forecasts as well as special statements and avalanche warnings during times <br />of significantly increased avalanche danger. Additionally, the NWAC maintains and manages a <br />comprehensive network of 25 remote mountain weather stations that provide hourly weather data to users <br />and cooperators alike. <br />7.3. SECONDARY HAZARDS <br />Avalanches can cause several types of secondary effects, such as blocking roads, which can isolate residents <br />and businesses and delay commercial, public and private transportation. This could result in economic <br />losses for businesses. Other potential problems resulting from avalanches are power and communication <br />failures. Avalanches also can damage rivers or streams, potentially harming water quality, fisheries and <br />spawning habitat. <br />7.4. CLIMATE CHANGE IMPACTS <br />Snow avalanches are mainly ruled by temperature fluctuations, heavy precipitation and wind regimes. With <br />rising temperatures and higher intensity storm events, climate change is likely to increase the frequency <br />and magnitude of both ordinary and extreme avalanche events. Melting of the permafrost layer has an <br />additional impact on the increase in avalanches. However, these possible changes are not taken into account <br />in current engineering practice: reference scenarios and return periods for avalanche hazard management <br />are always computed under the assumption of a stationary process. Unlike other phenomena such as tropical <br />storms, snow avalanches are rarely used as indicators of climate change. <br />7.5. EXPOSURE <br />There is minimal development in the high Cascade Range, which makes Kittitas County’s exposure to an <br />avalanche small. Most mountainous areas in the county are part of the Mount Baker-Snoqualmie National <br />Forest and other protected forests. <br />7.5.1 Population <br />There are no major populations exposed to avalanches in the county. Most of the avalanche hazard area is <br />uninhabited or has minimal development. Ski resorts are not considered to be exposed to avalanches due to <br />their ski slope maintenance protocols; however, skiers who ski out of bounds in these areas are exposed to <br />avalanches. People working in the mountains, such as miners and loggers, are exposed, as are recreational <br />users, such as hikers and cross-country skiers. <br />7.5.2 Property <br />There is little property that is exposed to avalanches. Property and buildings exposed include National <br />Forest huts and temporary structures belonging to mining and forestry operations. <br />7.5.3 Critical Facilities and Infrastructure <br />Interstate 90 could be blocked by avalanches, but the Washington State Department of Transportation <br />(WSDOT) conducts active winter avalanche control or mitigation on Interstate 90. This means avalanches <br />are triggered intentionally on slopes above the roadways in a controlled environment to minimize traffic <br />disruption and promote public safety. WSDOT also conducts passive avalanche control by building <br />elevated roadways so avalanches can pass under highways, snow sheds so that avalanching snow flows