930 AM PST WED DEC 12 2007
 
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ZONE AVALANCHE FORECASTS

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


SNOWPACK ANALYSIS

Most areas have received an additional trace to 2 inches 
of recent snow that fell with briefly moderate crest 
level northwest winds overnight Tuesday.


In general, several weak disturbances over the past week 
have deposited a cumulated total of about 2 to 8 inches 
of snow, with slightly greater amounts in the north near 
Mt Baker, and in the south on Mt Hood where up to 10 
inches has accumulated. This recent snow has fallen at 
cold temperatures and overlies a strong rain crust formed 
after the heavy rains 9 days ago. 

The shallow loose surface snow in most places and the 
strong underlying crust are producing a low avalanche 
danger in most areas. 

It should be noted that last weeks widespread avalanche 
cycle produced numerous large slides that released to 
near the ground. This has resulted in many slopes where 
only a very shallow snow cover remains above the old 
early season crust. Cool weather over the past week and 
earlier in November has continued to weaken and facet the 
snow near crusts and near the ground. Also, surface hoar 
frost has formed may of the past few nights and should be 
noted when future heavy snow loading occurs. 

Some windy periods over the past several days may have 
formed isolated pockets of wind slab on some steep lee 
slopes mainly at higher elevations near ridges where 
caution is advised. 


FORECASTS

WEDNESDAY THROUGH THURSDAY

Mostly cloudy conditions, cool temperatures and generally 
light to moderate crest level winds are expected 
Wednesday. A period of light snow is expected Wednesday 
night however this should not appreciably affect the 
current danger. 

Another weak disturbance should deposit additional light 
snowfall at cool temperatures late Thursday and Thursday 
night along with moderate crest level winds. This may 
cause a slight increase in danger, mainly near ridges at 
higher elevations as a few pockets of wind slab may form. 
On more protected slopes loose shallow snow over a firm 
crust should maintain mostly a stable snowpack.

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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