Avalanche Forecast

A strong low pressure system will move west to east across Washington on Monday. There should be a big difference in the weather and avalanche conditions between the north and south Cascades with the strongest winds and heaviest snowfall in the south Cascades. Right now it looks like the main effects of the low may reach as far north as the central Cascades. But a different track of the low could bring much different than expected weather and avalanche conditions on Monday so the forecast is somewhat uncertain.

Light to moderate winds and snow are expected in the north Cascades on Monday. Stronger shifting winds, moderate to heavy snow and rapid loading are expected in the central to south Cascades. New storm slab and wind slab potential will be greatest in the central to south Cascades. Back country travel is not recommended above treeline in the central and south Cascades on Monday. Dangerous avalanche conditions are expected in the other areas along the east slopes.

Terrain anchors are still causing significant anchoring at the lowest elevations and barely hidden hazards like rocks, streams or snags remain.

A series of cool storms has deposited increasing storm snow at relatively low freezing levels since early December. There has been about .5-2 feet of snowfall at sites along the east slopes the past 2-4 days. The skiing in non-wind affected areas with enough snow cover has been good! 

NWAC pro observer Tom Curtis was at Rainy Pass near Stevens Pass on Wednesday and noted extensive surface hoar. This layer may have been buried intact Thursday though no evidence of avalanches due to the layer have been reported.

Tom visited Mt Cashmere via the Icicle Creek drainage Thursday and did not find the persistent layer of buried surface hoar seen prior to the rain event December 8-9. There has been good evidence that the rain event destroyed this layer along the east slopes so the PWL has been removed as an avalanche problem along the east slopes. Tom did note small storm and wind slab up to near treeline but did not venture higher.

A guide report from Thursday at Washington Pass zone indicated good snow and good stability at the elevation of the highway hairpin with blowing snow along the ridge tops.

The Mission Ridge pro patrol on Friday reported widespread sensitive 4-8 inch storm slab avalanches but then reported no signficant avalanche activity on Saturday.

A back country skier on Mt Cashmere on Saturday found about 5 inches of new snow and a right side up upper snow pack with no results from snow pit tests and ski cuts.

The southeast zone should have a much shallower snowpack, more affected by recent rain and warm temperatures. However, we have no recent observations from the southeast zone.