Avalanche Forecast

Archived

Feb 8th, 2019–Feb 9th, 2019

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Snoqualmie 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.

Problems

Wind Slabs

Wind Slab avalanches are the 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.