000 WWUS86 KSEW 191808 SABSOR BACKCOUNTRY AVALANCHE FORECAST FOR THE OLYMPICS WASHINGTON CASCADES AND MT HOOD AREA NORTHWEST WEATHER AND AVALANCHE CENTER SEATTLE WASHINGTON 0930 AM PST FRI NOV 11 2005 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 applies to back country avalanche terrain below 7000 feet and does not apply to highways or operating ski areas. WAZ012-017-018-019-025-042-ORZ011-121800- && ZONE AVALANCHE FORECASTS OLYMPICS, WASHINGTON CASCADES NEAR AND WEST OF THE CREST- Moderate avalanche danger above 6000 feet and low below Friday. Increasing danger Friday afternoon and night and becoming considerable above 5000 feet and moderate below through early Saturday. Slowly decreasing danger during the day Saturday becoming considerable above 6000 feet and moderate below. Danger increasing Saturday night becoming high above 5-6000 feet and considerable below. MT HOOD AREA- Low avalanche danger below 7000 feet Friday. Increasing danger Friday afternoon and night and becoming considerable above 6000 feet and moderate below through early Saturday. Slowly decreasing danger during the day Saturday. Danger increasing Saturday night becoming high above 5-6000 feet and considerable below. EAST SLOPES WASHINGTON CASCADES- Low avalanche danger below 7000 feet early Friday slightly increasing Friday afternoon. Danger slowly increasing Friday night and early Saturday becoming moderate below 7000 feet. Avalanche danger slowly decreasing Saturday. Danger increasing Saturday night becoming considerable above 5000 feet and moderate below. OUTLOOK SUNDAY- Further increasing danger expected early Sunday becoming high above 4 to 5000 feet and considerable below west slopes Cascades and Olympics. Increasing danger east slopes of the Cascades early Sunday becoming considerable above 5000 feet and moderate below. Danger slowly decreasing later Sunday all areas. SNOWPACK ANALYSIS Little or no new snow has accumulated over the past few days. Recent high freezing levels Wednesday and Thursday have produced very warm temperatures with relatively light winds especially at higher elevations. This has allowed for significant snowpack settlement and stabilization of unstable layers formed early this week and during the heavy snow accumulations last week. Cooling temperatures Thursday night and early Friday have allowed for a strong surface crust to form in most areas. Early reports from about 6800 feet on Crystal Mountain early Friday indicated the surface crust was about 1 inch thick and not quite strong enough to support a person in boots. This strong surface or near surface crust is helping to limit the chance of triggered or natural avalanches and is currently producing mostly stable snow and a low danger in most areas as of early Friday. Above about 6000 feet along most west slope areas and Olympics some isolated areas of old wind slab may still persist however mainly in the north Washington Cascades where cooler temperatures may have limited crust formation. In these areas a moderate danger is expected with the possibility of some human triggered avalanches, mainly on very steep slopes near ridges and open slopes void of a strong crust. Although a gradually increasing snowpack is also developing along the Cascade east slopes and at lower elevations, significant terrain or vegetative anchors remain and these are helping to limit the danger to steeper snow covered terrain having a smooth underlying ground surface. FRIDAY, FRIDAY NIGHT- Moderate snow showers should spread from the Olympics to the Cascades near midday Friday and southward Friday afternoon, along with increasing ridgetop winds and very slight warming. This weather should produce gradually rising danger, especially on lee slopes above 5 to 6000 feet. At lower elevations, lighter winds are expected, however a moderate danger is still likely, especially on steeper lee terrain. Moderate snow showers and moderate to strong crest level winds Friday night at low freezing levels should further increase the avalanche danger. SATURDAY, SATURDAY NIGHT- Light to moderate snow showers with moderate winds early Saturday should maintain existing dangers. Decreasing showers and diminishing winds later Saturday should allow for a slow decrease in the danger as unstable layers settle and stabilize. Increasing snow and rain with rising freezing levels and very strong winds Saturday night should lead to a significantly increasing danger with natural or triggered slides becoming increasingly likely, especially above about 5000 feet. OUTLOOK SUNDAY- Moderate to heavy rain or snow with strong winds early Sunday should maintain or slightly increase the danger. Decreasing rain or snow showers with cooling and diminishing winds later Sunday should lead to a slowly decreasing danger. && Backcountry travelers should be aware that elevation and geographic distinctions are approximate and that a transition zone between dangers exists. Remember there are avalanche safe areas in the mountains during all levels of avalanche danger. Contact local authorities in your area of interest for further information. 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. Kramer/Northwest Weather and Avalanche Center $$