####018004213#### WWUS86 KPQR 211907 SABOR Summary Avalanche Forecast for Mt Hood area Northwest Weather and Avalanche Center Seattle Washington 1207 PM PDT Wed Mar 21 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 WEDNESDAY... Wednesday and Wednesday night: High avalanche danger below 7000 feet Wednesday slowly decreasing Wednesday night. Human triggered avalanches very likely. Thursday and Thursday night: High avalanche danger above 6000 feet and considerable below Thursday with slightly increasing danger on sun exposed terrain during midday and afternoon hours. Danger gradually decreasing Thursday night...becoming considerable above 4000 feet and moderate below. Snowpack Synopsis Increasingly heavy snow arrived late Monday night and continued in the Mt Hood area throughout Tuesday into early-mid Wednesday as a strong front stalled over southern WA and northern OR. This substantially loaded a variety of weak snow layers from earlier in the week and created increasingly dangerous avalanche conditions along with generally high danger Tuesday into Wednesday morning. With human triggered avalanches very likely, and the consequences of such slides very severe...back country travel in avalanche terrain is not recommended and slopes showing evidence of significant wind transport should be avoided. Wednesday and Wednesday night Periods of moderate to heavy snow and moderate ridgetop winds should continue for most of Wednesday before slowly decreasing later Wednesday night and early Thursday as the front slowly pushes east. This should 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 as compared to Tuesday, 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 should be avoided 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. 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...with one such incident already reported near Mt Hood Meadows late Tuesday. No matter where you go, Do Not Travel Alone! Ski or Ride with a partner! Thursday and Thursday night Light to occasionally moderate showers should slightly increase during midday and afternoon hours. Along with relatively light winds, continued low freezing levels, and very minor new snow accumulations...this weather should allow recent unstable slabs to slowly settle and begin to stabilize on Thursday. However, significant instability should continue on lee slopes where large but sensitive slabs should very slowly settle. This weather should also produce a local danger increase on sun exposed terrain where the potential for loose or isolated slabs should increase. As a result, increasing caution is advised on both lee slopes and steeper sun exposed terrain on Thursday. Decreasing showers and some clearing Thursday night should allow for decreasing danger as recent slabs continue to settle and weak surface crusts form on previously sun exposed slopes. 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/####018006392#### WWUS86 KSEW 211907 SABWA Summary Avalanche Forecast for Olympics and Washington Cascades Northwest Weather and Avalanche Center Seattle Washington 1207 PM PDT Wed Mar 21 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 the crest north of White Pass- Wednesday and Wednesday night: High avalanche danger above 5000 feet and considerable below early Wednesday. Danger slightly decreasing overall on Wednesday except slightly increasing on any sun exposed terrain where locally high danger is likely above about 4000 feet. Danger slightly increasing Wednesday night. Thursday and Thursday night: Considerable avalanche danger below 7000 feet early Thursday slightly increasing later morning and afternoon hours on sun exposed terrain. Danger decreasing Thursday night becoming considerable above 5000 feet and moderate below. Washington Cascades near and west of the crest from White Pass southward- ...AVALANCHE WARNING FOR WEDNESDAY... Wednesday and Wednesday night: High avalanche danger below 7000 feet Wednesday slowly decreasing Wednesday night. Human triggered avalanches very likely. Thursday and Thursday night: High avalanche danger above 6000 feet and considerable below Thursday with slightly increasing danger on sun exposed terrain during midday and afternoon hours. Danger gradually decreasing Thursday night...becoming considerable above 4000 feet and moderate below. Washington Cascade east slopes- Wednesday and Wednesday night: High avalanche danger on lee slopes above 5000 feet and considerable elsewhere slowly decreasing Wednesday except for slight increase on sun exposed terrain where locally higher danger is expected. Danger slightly increasing Wednesday night. Thursday and Thursday night: Considerable avalanche danger above 4000 feet and moderate below slightly increasing during midday and afternoon hours on sun exposed terrain. Danger decreasing Thursday night and becoming considerable above 5000 feet and moderate below. Snowpack Synopsis Increasingly heavy snow arrived late Monday night and continued in most areas for most of Tuesday before slowly decreasing early Wednesday. This loaded a variety of weak snow layers from earlier in the week and created very dangerous avalanche conditions in most areas along with generally high danger on Tuesday in most locations. However, gradually decreasing winds occurred later Tuesday into early Wednesday in the Olympics, along the Cascade east slopes, and Cascade west slopes north of about White Pass. This allowed for slow settlement of the earlier very unstable slabs while adding increasing amounts of lower density and more stable snow over the older and slowly settling slabs. While this produced a slight decrease in the danger from earlier warning conditions, significant unstable slabs persist beneath the more stable surface snow. Meanwhile, from about White Pass southward where the recent front stalled....prolonged and stronger winds combined with heavier snowfall to produce generally high danger and continued avalanche warning conditions Wednesday. Wednesday and Wednesday night In the Olympics, northern and central Cascades north of White Pass, and along the Cascade east slopes, light to moderate showers and generally light winds Wednesday should allow for a slow and slight decrease from the recent high danger. Meanwhile further to the south...moderate to occasionally heavy showers and stronger winds should help maintain generally high danger and avalanche warning conditions. Except for a local danger increase on sun exposed terrain where locally higher danger is likely, this weather overall should allow for a slow decrease in the danger in the Olympics, northern and central Cascades. However expected weather should maintain generally high danger in the south where human triggered slides should remain very likely in most locations. Increasing light to moderate snow or snow showers should slowly spread northward late Wednesday and overnight. This should produce a slight increase in the danger. However, some shallow new soft slabs are possible in higher terrain...and these more stable new snow accumulations should mask and continue to add further loading to underlying and previously sensitive and unstable wind slabs formed Tuesday. As a result, 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. Also, some very large and unstable cornice formations should persist 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! Thursday and Thursday night Light to occasionally moderate showers should slightly increase during midday and afternoon hours. Along with relatively light winds, continued low freezing levels, and very minor new snow accumulations...this weather should allow recent unstable slabs to continue to slowly settle and stabilize on Thursday. However, it should also produce a local danger increase on sun exposed terrain where the potential for loose or isolated slabs should increase. Decreasing showers and some clearing Thursday night should allow for decreasing danger. 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/