####018004993#### WWUS86 KSEW 052105 SABWA Summary Avalanche Forecast for Olympics and Washington Cascades Northwest Weather and Avalanche Center Seattle Washington 1304 PM PST Thu Jan 05 2012 This forecast applies to back country avalanche terrain below 7000 feet and does not apply to developed ski areas or highways. Corrected northwest WA zone forecast. Avalanche Forecast Washington Cascades Near and West of Crest north of Stevens Pass- Thursday: Considerable avalanche danger above 5000 feet and moderate below. Danger gradually decreasing Thursday night. Friday: Further decreasing danger becoming considerable on lee slopes above 5000 feet and moderate elsewhere. Further slow decreasing danger Friday night. Outlook Saturday: Moderate avalanche danger below 7000 feet with locally enhanced danger above 6000 feet on previous lee slopes. Overall decreasing danger Saturday. Olympics- Washington Cascades Near and West of the Crest Stevens Pass south- East slopes Washington Cascades north of Stevens Pass- Thursday: Considerable avalanche danger above 5000 feet and moderate below. Danger gradually decreasing Thursday night. Friday: Further decreasing danger becoming considerable on lee slopes above 6000 feet and moderate elsewhere. Further slow decreasing danger Friday night. Outlook Saturday: Moderate avalanche danger below 7000 feet with locally enhanced danger above 6000 feet on previous lee slopes. Overall decreasing danger Saturday. East slopes Washington Cascades Stevens Pass south- Thursday: Considerable avalanche danger on lee slopes above 6000 feet and moderate below and gradually decreasing. Danger further gradually decreasing Thursday night. Friday: Further decreasing danger becoming moderate below 7000 feet with locally enhanced danger above 6000 feet on previous lee slopes. Further slow decreasing danger Friday night. Outlook Saturday: Moderate avalanche danger below 7000 feet and overall decreasing Saturday. Snowpack Synopsis A frontal band on Wednesday caused rain to relatively high elevations before cooling changed rain to snow early Thursday. Rain likely reached to 6000 feet in the north and 6 to 7000 feet in the south. Very strong winds with the front late Wednesday through early Thursday have likely built areas of unstable wind slab layers on exposed lee slopes. These lee slopes range from north facing to east and southeast facing with the greatest danger having likely developed in the Mt Baker area where greater percipitation occurred. Thus the greatest current danger is expected from newly formed wind slab layers, mainly above 5 to 6000 feet on steep open lee slopes where triggered slides remain likely. Less new snow above a wet and slowly refreezing snowpack at lower elevations and on windward slopes are maintaining a significantly lower avalanche danger. Thursday Strong moist westerly flow following a frontal passage late Wednesday should maintain occasional light snow showers, mainly nearer the crest, with a further slow cooling trend. The strong winds and new snow should continue to load some lee slopes, especially on northeast to southeast facing slopes at higher elevations. At lower elevations shallow new snow layers should gradually build over a gradually refreezing surface. Friday Cool and mostly cloudy weather is expected Friday. Winds should be light Friday with freezing levels remaining low. This weather should help to stabilize previous unstable layers reducing the likelihood of triggering slab avalanches. That said, continue to assess previously loaded steep open slopes at higher elevations where some dangerous avalanche conditions may remain. At lower elevations strengthening crust layers with shallow recent snow should maintain a moderate danger, confining any unstable layers to specific terrain features where some earlier wind loading may have occurred. Saturday Outlook Mainly just high level clouds are expected Saturday with continued cool temperatures and light winds. This weather should allow for a further gradual decrease in danger. Older wind slab layers should have mostly settled and stabilized by Saturday. However, continue to assess local conditions, especially in areas that have received the most recent snowfall. 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 Seattle Washington References 1. http://www.nwac.us/ ####018004990#### WWUS86 KSEW 052105 SABWA Summary Avalanche Forecast for Olympics and Washington Cascades Northwest Weather and Avalanche Center Seattle Washington 1304 PM PST Thu Jan 05 2012 This forecast applies to back country avalanche terrain below 7000 feet and does not apply to developed ski areas or highways. Corrected northwest WA zone forecast. Avalanche Forecast Washington Cascades Near and West of Crest north of Stevens Pass- Thursday: Considerable avalanche danger above 5000 feet and moderate below. Danger gradually decreasing Thursday night. Friday: Further decreasing danger becoming considerable on lee slopes above 5000 feet and moderate elsewhere. Further slow decreasing danger Friday night. Outlook Saturday: Moderate avalanche danger below 7000 feet with locally enhanced danger above 6000 feet on previous lee slopes. Overall decreasing danger Saturday. Olympics- Washington Cascades Near and West of the Crest Stevens Pass south- East slopes Washington Cascades north of Stevens Pass- Thursday: Considerable avalanche danger above 5000 feet and moderate below. Danger gradually decreasing Thursday night. Friday: Further decreasing danger becoming considerable on lee slopes above 6000 feet and moderate elsewhere. Further slow decreasing danger Friday night. Outlook Saturday: Moderate avalanche danger below 7000 feet with locally enhanced danger above 6000 feet on previous lee slopes. Overall decreasing danger Saturday. East slopes Washington Cascades Stevens Pass south- Thursday: Considerable avalanche danger on lee slopes above 6000 feet and moderate below and gradually decreasing. Danger further gradually decreasing Thursday night. Friday: Further decreasing danger becoming moderate below 7000 feet with locally enhanced danger above 6000 feet on previous lee slopes. Further slow decreasing danger Friday night. Outlook Saturday: Moderate avalanche danger below 7000 feet and overall decreasing Saturday. Snowpack Synopsis A frontal band on Wednesday caused rain to relatively high elevations before cooling changed rain to snow early Thursday. Rain likely reached to 6000 feet in the north and 6 to 7000 feet in the south. Very strong winds with the front late Wednesday through early Thursday have likely built areas of unstable wind slab layers on exposed lee slopes. These lee slopes range from north facing to east and southeast facing with the greatest danger having likely developed in the Mt Baker area where greater percipitation occurred. Thus the greatest current danger is expected from newly formed wind slab layers, mainly above 5 to 6000 feet on steep open lee slopes where triggered slides remain likely. Less new snow above a wet and slowly refreezing snowpack at lower elevations and on windward slopes are maintaining a significantly lower avalanche danger. Thursday Strong moist westerly flow following a frontal passage late Wednesday should maintain occasional light snow showers, mainly nearer the crest, with a further slow cooling trend. The strong winds and new snow should continue to load some lee slopes, especially on northeast to southeast facing slopes at higher elevations. At lower elevations shallow new snow layers should gradually build over a gradually refreezing surface. Friday Cool and mostly cloudy weather is expected Friday. Winds should be light Friday with freezing levels remaining low. This weather should help to stabilize previous unstable layers reducing the likelihood of triggering slab avalanches. That said, continue to assess previously loaded steep open slopes at higher elevations where some dangerous avalanche conditions may remain. At lower elevations strengthening crust layers with shallow recent snow should maintain a moderate danger, confining any unstable layers to specific terrain features where some earlier wind loading may have occurred. Saturday Outlook Mainly just high level clouds are expected Saturday with continued cool temperatures and light winds. This weather should allow for a further gradual decrease in danger. Older wind slab layers should have mostly settled and stabilized by Saturday. However, continue to assess local conditions, especially in areas that have received the most recent snowfall. 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 Seattle Washington References 1. http://www.nwac.us/