Avalanche Forecast
Regions: Stevens Pass.
Expect very dangerous avalanche conditions with avalanches likely. Cold, dry snow, strong wind, and old weak surfaces are contributing to High Danger. Stay well out from under steep slopes and avoid avalanche terrain above treeline.
Discussion
Snow and Avalanche Discussion
An avalanche warning has been issued for the neighboring East Central zone. A cold and gusty storm is impacting the Cascades. New snow and drifts are forming on weak old snow surfaces and slick crusts. You can trigger loose dry avalanches in wind-sheltered terrain, below treeline.
Cold temperatures have been weakening the upper snowpack. Observers have reported widespread weak facets and surface hoar at the surface prior to the storm. We’ve also received reports of some lingering interfaces in the top 2 feet of the snowpack. Expect the coldest temperatures of the season. Bring plenty of warm layers and take precautions against exposure to the cold and wind.
Snowpack Discussion
Regional Synopsis coming soon.
Avalanche Problems
Wind Slabs
You can trigger wind slab avalanches in open terrain at all elevations. Stay off of windward slopes 35 degrees and steeper. Steer around wind pillows and drifts. With drifts forming on old, weak snow, wind slab avalanches may be easier to trigger than you might expect. You may also be able to trigger these avalanches from further away than is typical.
Strong and gusty east wind with plenty of light dry snow will efficiently build slabs. Expect wind drifting below treeline at pass level. In less wind-affected areas, watch for triggering loose dry avalanches on slopes over 35 degrees.
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: All elevations.
Likelihood: Likely
Expected Size: 1 - 1