900 AM PST TUE DEC 11 2007
 
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ZONE AVALANCHE FORECASTS

* OLYMPICS, WASHINGTON CASCADES, MT HOOD AREA-
Moderate avalanche danger above about 5000 feet and low 
below Tuesday through Wednesday.


SNOWPACK ANALYSIS

In most areas relatively small amounts of recent snow or 
surface hoar frost are found on the stable thick crust 
formed during the heavy rain event a week ago. Yesterday 
morning most areas had received a trace to 3 inches of 
new snow that fell with light winds. Most areas now have 
between a trace to 4 inches of recent snow above the 
crust ranging up to about 7 to 8 inches at Mt Baker and 
Mt Hood where the greatest recent snow overlies the 
crust. 

Some isolated pockets of small wind slabs may have 
developed at higher elevations the past few days. For 
this reason we are forecasting a moderate danger above 
5000 feet. The emphasis should be near ridges on mainly 
steep southeasterly to southwesterly facing slopes at 
higher elevations. Elsewhere the soft shallow amounts of 
recent snow overlying the hard crust are maintaining 
stable snow and a low danger. Reports on the FOAC and TAY 
web sites also indicate light amounts of snow on the firm 
crust, good stability, and some good snow conditions at 
Mt Baker and locally at Mt Rainier.


There are also recent reports of small surface hoar 
development over the past few nights and this may also 
become a significant weak layer if buried and loaded by 
future snowfall. 

DETAILED FORECASTS

TUESDAY THROUGH WEDNESDAY

Increasing clouds are expected on Tuesday. Some very 
light amounts of snow are possible Tuesday night. Partly 
or mostly cloudy conditions are expected Wednesday. A 
little more very light snowfall is possible Wednesday 
night mainly in the Olympics and north Cascades. Crest 
level winds should become southwest on Tuesday and west 
to northwest on Wednesday. Milder temperatures may be 
seen at higher elevation west of the crest Tuesday.


This weather is not expected to cause significant change 
to snow conditions. Some isolated pockets of unstable 
snow might persist at higher elevations on some steep lee 
slopes near ridges. In most areas stable shallow amounts 
of recent soft snow should be found over a firm crust.


It should be noted that this weather may cause further 
surface hoar formation or faceting and weakening of the 
bond of recent snow to the crust. These may be important 
when future heavier snowfall occurs.


At lower elevations, the combination of light winds, a 
very shallow and in places patchy snow cover, and 
significant terrain and vegetative anchoring should all 
help to maintain a generally low danger and stable snow.


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