Avalanche Forecast

Strong southwest flow aloft will carry a very moist frontal system to the Northwest on Wednesday. This will cause stormy wet weather along the Cascade west slopes on Wednesday with rain and high snow levels. The most rain should be seen in the northwest zone at Mt Baker with several inches expected but pretty heavy rain should seen elsewhere along the Cascade west slopes. Some freezing rain may be seen near the Cascade Passes and at low elevations east of the crest. See the NWAC Mountain Weather Forecast for details.

Wednesday will be a potentially dangerous day along the Cascade west slopes. Natural or triggered large or very large loose wet and wet slab avalanches are likely or very likely on Wednesday depending on how much rain there is, how it percolates into the snowpack and if avalanches entrain deeper layers.

Observations and tests for loose wet avalanches are more straightforward such as wet surface snow deeper than a few inches, rollerballs and natural loose wet avalanche actiivity.

But observations and tests for wet slab avalanches are more difficult since it is usually hard to know the effects of significant amounts of water percolating into the snowpack.

Travel in avalanche terrain is not recommended along the Cascade west slopes on Wednesday.

Weather and Snowpack

The aftermath of the last storm cycle 2/8-2/10 left a very strong rain crust with whatever amount of new snow received above, except for areas exposed to west winds which remained scoured to the firm and slick crust.  

High pressure Saturday to Tuesday brought increasing sunshine and warm temperatures. Temperatures reached the 40's and 50's in many areas of the Olympics and Cascades by Monday and Tuesday. This caused a lot of snowpack settlement, some small loose wet avalanche activity and a decreasing avalanche danger.

Recent Observations

North

NWAC pro-observer Lee Lazzara was in the Mt Baker backcountry Saturday and reported a favorable increasing resistance profile in the storm snow over the very strong rain crust. Observations were not made in terrain where wind slabs may have formed. 

Central

A report via the NWAC Observations page indicated many small loose wet avalanches on the south side of Mt Lichtenberg on Sunday.

The Stevens Pass pro-patrol reported no avalanche activity on Monday.

South

The Crystal Mountain pro-patrol on Monday reported some rollerballs on solar slopes at lower elevations with wind cooling the ridges.

NWAC observer Dallas Glass was at Paradise Sunday and confirmed the recent wind and storm slabs have settled and stabilized. By Sunday afternoon, strong sunshine and temperatures into the mid 40's triggered numerous rollerballs from many steep sun exposed terrain features, especially rock features. There was evidence of numerous wet slab avalanches that released several days ago during the heavy rain event with average crown depths around 2 feet. The underlying rain crust is now very hard and supportive, with an average of about 10 inches of recent snow over the crust in wind sheltered terrain.