Why do avalanches occur?
Avalanches occur when a snow pack loses its grip on a slope and slides downhill. Typically, slopes between 20 to 30 degrees and snow packs of 34 inches or more may produce avalanches. Despite the fact that avalanche danger is highest during severe winter weather, most natural avalanches occur in back country little used by humans during such conditions. Uninhabited alpine areas in the Cascades north and south of I-90 experience hundreds of avalanches annually. As a result, this tends to minimize exposure to avalanche impacts. Most at risk are travelers and winter recreation enthusiasts using Steven’s Pass in northern King County, Snoqualmie Pass in central King County, and Crystal Mountain Ski Area near Chinook Pass in southern King County. Also at risk from avalanche events are recreation areas that support snowshoeing, alpine and cross-country skiing, snowmobile areas, and winter hikers and campers. Injuries to recreational hikers, skiers, snow boarders, and climbers usually occur ou
