WWUS86 KSEW 302010 SABNW MOUNTAIN WEATHER FORECAST FOR THE OLYMPICS WASHINGTON CASCADES AND MT HOOD AREA NORTHWEST WEATHER AND AVALANCHE CENTER SEATTLE WASHINGTON 130 PM PDT WED SEP 30 2009 NWAC Program administered by: USDA-Forest Service with cooperative funding and support from: Washington State Department of Transportation National Weather Service National Park Service Washington State Parks and Recreation Commission Pacific Northwest Ski Area Association Friends of the Avalanche Center and other private organizations. This forecast is prepared primarily for federal, state and private snow safety programs in Washington and Northern Oregon. WAZ513-518-519-019-042-501-502-ORZ011-012000- && FALL AVALANCHE STATEMENT As the winter season rapidly approaches, the Northwest Weather and Avalanche Center is preparing once again to provide daily avalanche forecasts for the Olympics and Cascades. These forecasts will become available in late November or December when sufficient snow has accumulated at moderate and lower elevations to create a potential avalanche danger. These forecasts to not apply to developed ski areas or highways. For your information a few general notes regarding fall avalanches follow . . . During the fall the atmosphere experiences significant cooling at higher latitudes. As this cold northern air is mixed progressively southward by fall storms, pronounced changes in the air temperatures over the Northwest are a characteristic result. These large temperature variations can result in rapid decreases in the snowpack stability in areas with sufficient snow to slide. Wet cool weather depositing substantial snowfall at the higher elevations followed by rapid warming still common in the fall can quickly produce greatly increased avalanche danger. In the fall this problem is usually confined to permanent snow fields on the volcanic peaks, as vegetation and other anchoring prevalent at lower elevations generally prevents slides of a shallow snow cover. Back-country travelers should make terrain, weather and snowpack stability evaluations as they travel over snow covered terrain. Remember that seemingly insignificant slides may be dangerous. Almost half of all avalanche fatalities occur in slides traveling less than 300 feet. Have a safe and enjoyable fall and winter! If you have any comments or suggestions regarding our avalanche forecasting program, please direct them to: Northwest Weather and Avalanche Center 7600 Sandpoint Way NE Seattle, WA 98115 You may email comments to: nwac.sew@noaa.gov NWAC weather data and forecasts are also available by calling 206-526-6677 for Washington, 503-808-2400 for the Mt Hood area, or by visiting our Web site at www.nwac.us. Ferber/Northwest Weather and Avalanche Center $$