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        Summary Avalanche Forecast for Olympics and Washington Cascades



   Northwest Weather and Avalanche Center Seattle Washington



   1348 PM PST Mon Feb 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 the crest



                WARNING FOR EXTREME AVALANCHE DANGER TUESDAY



   Monday: Slightly increasing considerable avalanche danger above 4000

   feet and moderate below Monday. Danger increasing Monday night.



   Tuesday: Avalanche danger becoming extreme above 4000 feet and high

   below Tuesday and continuing Tuesday night.



                    Washington Cascades east of the crest



                          AVALANCHE WARNING TUESDAY



   Monday: Slightly increasing considerable avalanche danger above 5000

   feet and moderate below Monday. Danger increasing Monday night.



   Tuesday: Avalanche danger becoming high above 4000 feet and

   considerable below Tuesday and continuing Tuesday night.



Snowpack Synopsis



   A strong front moved over the Northwest late Friday followed by an

   upper trough on Saturday. This caused strong winds and heavy snowfall

   in the Olympics and Cascades. Snowfall totals were heavy for Friday and

   Saturday and were mainly in the 2-3 foot range in the Olympics and

   Washington Cascadesnear and west of the crest.



   This heavy snowfall helped cause many natural and triggered avalanches

   at Hurricane and in the Washington Cascades Saturday and Sunday.

   Fatality accidents were seen at Stevens and Snoqualmie on Sunday. An

   injury accident was seen near Crystal Mountain on Sunday. This much

   activity obviously indicated a regionally unstable upper snow pack.

   While a little stabilizing should also have occurred on Sunday some

   unstable layers may persist on some steep slopes on Monday.



Monday



   A weak disorganized frontal system will cross the Northwest on Monday

   with the main part expected to move to Oregon. This should cause light

   or moderate winds, light snow and slight warming on Monday. This should

   not greatly change snow conditions but the slight warming should

   maintain warmer denser surface layers and maintain existing potential

   instability on some steep slopes. Careful snowpack evaluation and

   cautious route finding should be essential on Monday. Greater warming

   and increasing rain or snow should cause an increasing avalanche danger

   Monday night.



Tuesday



   The warm front portion of a strong system should reach the Northwest on

   Tuesday. This system is expected to be strongest in the Olympics and

   Washington Cascades. This should cause very strong winds, heavy rain

   and rising snow levels in this area. After the recent heavy snowfall

   these are about the best ingredients one can ask for avalanches. This

   should cause an avalanche cycle on Tuesday and Tuesday night with large

   or very large avalanche in many areas. Avoid avalanche terrain

   especially in the Olympics and near and west of the crest on Tuesday

   and Tuesday night.



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   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 Seattle Washington



References



   1. http://www.nwac.us/