Avalanche Forecast

A weak system will cross the Pacific Northwest Tuesday afternoon through Wednesday morning and should produce only light amounts of new snow along with a cooling trend.  Little to no precipitation is expected around Mt. Hood through Wednesday morning.  Light showers on Wednesday should increase in intensity in the late afternoon or evening, occasionally becoming moderate for the west slopes of the Cascades before a sharper drying and cooling trend takes hold Wednesday night.

New shallow wind slab may be found above treeline on elevations on Wednesday, generally on N through SE aspects. Although the recent warming has helped to stabilize the upper snowpack, weak layers may be still be found under Thursday's most recent snow and may be sensitive to the light additional loads received Tuesday night and Wednesday, especially for any areas that receive more snow than forecast.  

The last major storm to impact the mountains occurred over Thanksgiving weekend. This storm produced heavy rain followed by an arctic air mass that settled over the region and 1-2 feet of low density snow at sites near and west of the crest. Little avalanche activity was seen following the storm due to the cooling, good bonds to the newly formed December 1st crust, lack of wind and generally cohesionless new snow.

Dry, cold and locally windy weather followed during the first week of December. This produced local wind slab and scoured surfaces in exposed areas, and hoar frost and near surface faceted snow in sheltered areas.

Several hours of strong westerly winds and a warming trend hit the north Cascades last Thursday. This built pockets of shallow wind slab that produced some skier triggered releases at the Mt Baker ski area: releases failed on some of the recently buried hoar frost and/or near surface faceted snow.

About 2-9 inches of wet snow was seen late Thursday to Friday morning with the most at Paradise. This produced some more 6-12 inch skier triggered storm slab releases at the Mt Baker ski area on Friday and some shallow storm slab around Mt Hood Meadows.

The most important weather factor for most areas should be the warming that began Friday and continued through mid-day Tuesday on both sides of the Cascade crest. This should have mostly eliminated the strong temperature gradient that was in the upper snowpack. Warmer temperatures and weaker temperature gradients should have caused rounding of old hoar frost and faceted snow and should have helped consolidate and stabilize previous snow and wind slab layers in most areas.  A variety of mostly minor wet snow conditions are reported the past couple days such as small shallow wet loose avalanches, roller balls, pinwheels and shallow wet snow conditions such as from Hurricane, the Mt Baker ski area, Stevens, Snoqualmie and Mt Hood.

Shallow snow cover is limiting the avalanche danger at lower elevations.