Avalanche Forecast
Regions: Cascades - North East.
Watch for mostly small wind-loaded pockets on steeper terrain, particularly above treeline and especially in the northeast zone. Approach ridges cautiously and watch for firmer wind-transported snow.
Detailed Forecast
Sunny weather should be seen on Tuesday with light northeast winds and recent snow layers will continue to stabilize.Â
Small wind slabs should remain generally on NW through E aspects on Tuesday and should become more stubborn or difficult to trigger. Watch for areas of firmer, wind-transported snow mainly on lee terrain features.Â
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.
A series of frontal systems produced snow over the past week at all stations in the Cascades since the Thanksgiving warm period: Locations on the east side of the Cascade crest have received 5-15".
48 hour snow accumulation ending on Sunday, December 3 along the Cascade east slopes have been light, ranging from 1-8".
Dry and cool conditions Sunday and Monday have allowed for 1-3 inches of snowpack settlement and allowed recent storm layers to begin stabilizing
Observations
North
NWAC pro observer Jeff Ward was near Washington Pass 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 reacting to ski tests.
Central and South
On Saturday, backcountry professionals skiing at Ingalls Peak reported generally stable conditions with some small, unreactive wind slab.
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.
Likelihood: Possible
Expected Size: 1 - 1
Storm Slabs
Release of a soft cohesive layer (a slab) of new snow that breaks within the storm snow or on the old snow surface. Storm-slab problems typically last between a few hours and few days. Storm-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.
You can reduce your risk from Storm Slabs by waiting a day or two after a storm before venturing into steep terrain. Storm slabs are most dangerous on slopes with terrain traps, such as timber, gullies, over cliffs, or terrain features that make it difficult for a rider to escape off the side.
Storm slabs usually stabilize within a few days, and release at or below the trigger point. They exist throughout the terrain, and can be avoided by waiting for the storm snow to stabilize.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely
Expected Size: 1 - 1