Avalanche Forecast

Showers should wind down Wednesday morning with the next frontal system already moving in later Wednesday afternoon. Despite a modest cooling trend, storm related danger will continue through Wednesday due to strong southwest to west winds loading lee slopes during moderate showers Tuesday night. 

Storm slab instabilities should be healing but may still be sensitive Wednesday. Wind slab will continue to build Tuesday night on lee slopes with moderate to strong west transport winds. Loose wet avalanches will become more likely on steeper slopes in the afternoon as snow levels begin to rise once again. Avalanches that begin in the new snow may become larger lower down the path as they entrain moist or wet snow.  

With several avalanche problems to deal with Wednesday, conservative terrain selection will be essential to stay safe because human triggered avalanches are still likely. Choose moderately angled terrain and avoid wind loaded slopes, saving those steeper lines for another day.

Non-avalanche hazard: Despite our seasonally healthy snowpack, many creeks are open and difficult to cross due to the periodic warm temperatures and rain events.  

Weather and Snowpack

Springlike weather under high pressure Feb 23rd and 24th led to abundant sunshine with daytime highs climbing into the 40's and 50's. The fair and mild weather caused thick surface crusts, especially on solar slopes in most areas by Friday. 

A Pacific frontal system blew through the Cascades mid-day Sunday. The most significant transport winds were from the W-SW and seen early Sunday afternoon with gusts in the 40s or 50s below or near treeline with much stronger winds above treeline. By Monday morning, 4-12 inches of new snow had accumulated along the west slopes accompanied by a cooling trend. 

A warm front quickly dropped up to 10 inches of new snow early Tuesday morning at NWAC stations before snow either eased off mid-morning or changed to rain outside the Cascade Passes. Precipitation rates increased again in the afternoon as the cold front approached. In the Mt. Baker area, precipitation rates increased later in the morning with the snow level rising above 5000 ft during the day.  

The mid and lower snow pack along the west slopes should generally be a stable mix of crusts and layers of moist and rounded snow crystals.

Recent Observations

Crystal and Stevens Pass pro-patrol reported Monday that while wind loading was evident, wind loaded slopes were not very sensitive with only very small slabs releasing during control work. 

NWAC observer Tom Curtis was out at Jove Peak Monday. Jove Peak is NE of Stevens Pass and often overlaps snowpack characteristics of both the east and west slopes of the Cascades. Tom noted few instabilities in the upper snowpack until he observed a large natural wind slab avalanche (R2-D2) on the north side of Jove Peak that probably released Sunday night. The winds slab was 40 cm in depth and stepped down to a 2 mm buried surface hoar layer at 50 cm. The buried surface hoar was rounding, but clearly still sensitive to new loading. 

A storm day on Tuesday limited observations, but one observation submitted via the NWAC observation page from behind Windy Ridge near Stevens Pass reported increasing instability and sensitivity to triggering with a large soft slab avalanche on a WNW aspect running well and entraining moist snow lower in the path.