####018004192#### WWUS86 KPQR 201728 SABOR Summary Avalanche Forecast for Mt Hood area Northwest Weather and Avalanche Center Seattle Washington 1027 AM PDT Tue Mar 20 2012 This forecast applies to back country avalanche terrain below 7000 feet and does not apply to developed ski areas or highways. Avalanche Forecast Mt Hood area- ...AVALANCHE WARNING FOR TUESDAY AND WEDNESDAY... Tuesday and Tuesday night: Rapid and significantly increasing danger becoming high above 5000 feet and considerable below Tuesday morning. Natural or triggered avalanches increasingly likely. Further increasing danger Tuesday afternoon and night becoming high at all elevations Wednesday and Wednesday night: High avalanche danger below 7000 feet early Wednesday. Danger slightly decreasing later Wednesday morning and mid-day, but increasing again Wednesday afternoon and night. Snowpack Synopsis Over the last few days some 8 to about 20 inches of relatively low density snow has fallen...the most recent with light or decreasing winds. Also, the cold temperatures have produced some recrystallization and weakening of near surface snow while brief clearing in some locations has developed a layer of weak surface hoar. Along with slow settlement of the heavier snowfall received late last week, this weather has produced relatively stable accumulations of the most recent snowfall...which may be masking some buried but mostly shallow wind slabs at higher elevations. In any case, these weak surface snow conditions should not long sustain the heavy snow loading and strong winds that began last night and should continue for much of the next 24-48 hours...with significantly increasing danger already well underway. Tuesday and Tuesday night Periods of moderate to heavy snowfall and strong winds at relatively low freezing levels through Tuesday night should add substantial stress to one of several buried near surface weak layers and produce an increasingly sensitive and unstable snowpack in the Mt Hood area. High danger should rapidly develop above 5000 feet Tuesday morning...with increasing considerable danger elsewhere. This danger should continue to slowly increase and spread to lower elevations Tuesday afternoon and night. Travel in avalanche terrain is not recommended. Wednesday and Wednesday night Although briefly and slightly decreasing snowfall and shifting winds are expected Wednesday morning, increasingly heavy snow should redevelop Wednesday afternoon and night before slowly decreasing early Thursday. This should add further load to a number of buried weak layers, produce gradually thickening wind deposits and larger avalanche releases... and help maintain generally high danger and avalanche warning conditions in most steeper avalanche terrain though Wednesday evening. While generally less winds are likely on Wednesday, the slightly lighter but still denser surface snow should mask underlying very sensitive and unstable wind slabs formed Tuesday...and back country travel in avalanche terrain is still not recommended until the large amounts of new snow have had a chance to settle and begin to stabilize. Also, some very large and unstable cornice formations are likely and should be given a wide berth and great respect...and meanwhile the large amounts of recent unconsolidated snow present not only a substantial avalanche problem but also an increasing chance of deep snow burial or suffocation near tree wells. No matter where you go, Do Not Travel Alone! Ski or Ride with a partner! n/a n/a 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. Moore/Northwest Weather and Avalanche Center Seattle Washington References 1. http://www.nwac.us/####018006176#### WWUS86 KSEW 201728 SABWA Summary Avalanche Forecast for Olympics and Washington Cascades Northwest Weather and Avalanche Center Seattle Washington 1027 AM PDT Tue Mar 20 2012 This forecast applies to back country avalanche terrain below 7000 feet and does not apply to developed ski areas or highways. Avalanche Forecast Olympics- Washington Cascades near and west of crest from Snoqualmie Pass northward- ...AVALANCHE WARNING FOR TUESDAY THROUGH EARLY WEDNESDAY... Tuesday and Tuesday night: Rapid and significantly increasing danger becoming high above 4000 feet and considerable below Tuesday morning. Natural or triggered avalanches increasingly likely. Further gradually increasing danger Tuesday afternoon and night. Wednesday and Wednesday night: High avalanche danger above 4000 feet and considerable below slightly decreasing later Wednesday morning and early afternoon and becoming high above 5000 feet and considerable below. Danger slightly increasing later Wednesday afternooon and night. Olympics- Washington Cascades near and west of crest south of Snoqualmie Pass- ...AVALANCHE WARNING FOR TUESDAY AND WEDNESDAY... Tuesday and Tuesday night: Rapid and significantly increasing danger becoming high above 4000 feet and considerable below Tuesday morning. Natural or triggered avalanches increasingly likely. Further increasing danger Tuesday afternoon and night. Wednesday and Wednesday night: High avalanche danger below 7000 feet early Wednesday. Danger slightly decreasing later Wednesday morning and mid-day, but increasing again Wednesday afternoon and night. Washington Cascade east slopes- Tuesday and Tuesday night: Rapid and significantly increasing danger becoming high above 5000 feet and considerable below Tuesday. Natural or triggered avalanches increasingly likely. Further increasing danger Tuesday night. Wednesday and Wednesday night: High avalanche danger above 5000 feet and considerable below slightly decreasing Wednesday morning, slightly increasing Wednesday afternoon and night...especially south and central. Danger decreasing again late Wednesday night. Snowpack Synopsis Over the last three days some 8 to about 20 inches of relatively low density snow has fallen...the most recent with light or decreasing winds. Also, the cold temperatures have produced some recrystallization and weakening of near surface snow while brief clearing in some locations has developed a layer of weak surface hoar. Along with slow settlement of the heavier snowfall received late last week, this weather has produced relatively stable accumulations of the most recent snowfall...which may be masking some buried but mostly shallow wind slabs at higher elevations. In any case, these weak surface snow conditions should not long sustain the heavy snow loading and strong winds that began last night and should continue for much of the next 24-48 hours...especially in the south where heaviest and most prolonged snowfall is likely. In most areas...significantly increasing avalanche danger is already well underway. Tuesday and Tuesday night Periods of moderate to heavy snowfall and strong winds at relatively low freezing levels on Tuesday should add substantial stress to one of several buried near surface weak layers and produce an increasingly sensitive and unstable snowpack in all areas. High danger should rapidly develop above 4000 feet in the Olympics and Cascades near and west of the crest, and above 5000 feet along the Cascade east slopes...with increasing considerable danger elsewhere. Travel in avalanche terrain is not recommended until the recent large amounts of snow have begun to settle and slowly stabilize. Also, some very large and unstable cornice formations are likely and should be given a wide berth...and the large amounts of recent unconsolidated snow present not only a substantial avalanche problem but also an increasing chance of deep snow burial or suffocation near tree wells. No matter where you go, Do Not Travel Alone! Ski or Ride with a partner! Wednesday and Wednesday night Briefly decreasing light to moderate snow should allow for some settlement and a slight danger decrease in the Olympics and most of the WA Cascades Wednesday morning. However, moderate to heavy snow should spread northward midday and Wednesday afternoon, and this should add further load to buried weak layers and maintain avalanche warning conditions in most areas along the Cascade crest and west slopes south of Snoqualmie Pass through late Wednesday. From about Snoqualmie Pass northward and in the Olympics, less snowfall and winds Wednesday morning should allow for a slow and slight danger decrease. However, increasing snow or snow showers slowly spreading northward Wednesday afternoon and night should produce another slow but less significant increase in the danger as generally lighter winds are expected further north. While generally less winds are likely on Wednesday, the slightly lighter but still relatively dense surface snow (as compared with the recent snow from Sunday and Monday) should mask underlying very sensitive and unstable wind slabs formed Tuesday...and back country travel in avalanche terrain is still not recommended until the large amounts of new snow have had a chance to further settle and stabilize. n/a n/a 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. Moore/Northwest Weather and Avalanche Center Seattle Washington References 1. http://www.nwac.us/