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        Summary Avalanche Forecast for Olympics and Washington Cascades



   Northwest Weather and Avalanche Center Seattle Washington



   1243 PM PST Wed Feb 22 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-





   Wednesday: High avalanche danger above 5000 feet and considerable below

   with the greatest danger on lee slopes. Slowly decreasing danger late

   Wednesday and Wednesday night.



   Thursday: Considerable avalanche danger above 5000 feet and moderate

   below and slowly decreasing. Further slowly decreasing danger Thursday

   night.



Snowpack Synopsis



   Very strong frontal precipitation began late Monday lasting through

   Tuesday night followed by a strong cold frontal passage early

   Wednesday. This system deposited very heavy precipitation amounts at

   rising freezing levels along with very strong winds.  Precipitation

   amounts with this system mostly ranged from about 2 to nearly 6 inches

   of water equivalent as of early Wednesday. Less precipitation was

   received at Hurricane Ridge in the Olympics due to blocking

   topography.  Rain or heavy wet snow fell to about 4000 feet in the

   north and southward to about Stevens Pass. Rain reached about 6000 feet

   central and 7000 feet south.



   At higher elevations, especially from about Mt Baker to Stevens Pass,

   there may be significantly deep new dense storm or wind slab layers as

   precipitation remained as snow during the entire storm. Some deep slab

   layers of 3 to 6 feet or more are possible in these areas. As cooling

   and additional snow showers occur early Wednesday, a gradual shift to

   newly forming wind slabs should take place.



Wednesday



   A strong cold frontal passage moved across the area early Wednesday

   causing heavy precipitation at cooling temperatures and very strong

   crest level westerly winds. This has likely begun to build new wind

   slab layers on lee slopes gradually to lower elevations. The greatest

   danger is expected on steeper north to southeast facing slopes above

   about 5000 feet, with shallower wind slabs forming on these aspects at

   lower elevations as well.



   Showers and strong westerly flow should continue through Wednesday

   causing further slow loading on lee slopes. Deep wet snow conditions

   are expected at lower elevations that have received heavy rains. These

   wet snow conditions should begin to gradually refreeze as cooling

   continues later Wednesday.



Thursday



   A relative break in the stormy recent weather pattern is expected

   Thursday as high pressure rebuild over the area. Expected partly to

   mostly cloudy weather with cool temperatures and light winds. This

   should allow for a decreasing danger Thursday as unstable storm or wind

   slab layers slowly settle and bond. However, the cold temperatures

   should slow this process and unstable slab layers are likely to persist

   in steeper lee terrain at higher elevations. Careful snowpack

   evaluation, cautious routefinding and conservative decision-making will

   be essential in higher elevation terrain.



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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.

   Kramer/Northwest Weather and Avalanche Center Seattle Washington



References



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