Avalanche Forecast
Regions: Cascades - North East.
Watch for mostly small wind-loaded pockets pockets on steeper terrain, particularly in the near and above treeline and particularly in the northeast zone. Approach ridges cautiously and watch for firmer wind-transported snow.
Detailed Forecast
Light showers Saturday night and Sunday morning should decrease from the north with light NNW winds. See the NWAC mountain weather forecast tab for more details.Â
Although new snow amounts the past week have been light, near and above treeline winds were capable of transporting snow and building wind slab near Washington Pass and potentially other locations along the east slopes. Due to scare observations, careful snowpack evaluation is important, particularly near ridgelines and exposed terrain features.
Most storm slabs are expected to have stabilized by this time along the east slopes.
Early season terrain hazards still exist, such as poorly covered rocks, vegetation and creeks, particularly at lower elevations.
Snowpack Discussion
Warm, wet weather before Thanksgiving caused first storm then wet snow avalanches in the Washington Pass area.  Post-Thanksgiving about 2 feet of snow accumulated in the Washington Pass area and this amount has settled above the Thanksgiving Day crust.
During the past week, a series of frontal systems have generally produced light amounts to about a foot of new snow along the east slopes of the Cascades, with the most in the northeast Cascades. Total snow is limited in the central-east and southeast Cascades. Temperatures at Washington Pass were generally upper teens and low 20's; Winds were generally SW in the 10's.
Observations
North
NWAC pro observer Jeff Ward was in the Twisp River drainage on Tuesday and found 30-50 cm of low density snow on the Thanksgiving crust. Some small loose dry avalanches were triggered late in the day. There was evidence of buried wind slab, but the layers were not reactive to ski tests.
Central and South
No recent observations.
Avalanche Problems
Wind Slabs
Release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Wind Slabs form in specific areas, and are confined to lee and cross-loaded terrain features. They can be avoided by sticking to sheltered or wind-scoured areas..
Wind Slab avalanche. Winds blew from left to right. The area above the ridge has been scoured, and the snow drifted into a wind slab on the slope below.
Wind slabs can take up to a week to stabilize. They are confined to lee and cross-loaded terrain features and can be avoided by sticking to sheltered or wind scoured areas.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1