Avalanche Forecast
Regions: Snoqualmie Pass.
Happy New Year! New Year’s Day should be a beautiful day to be in the mountains. Don’t let the nice weather fool you. You may still trigger avalanches in wind loaded areas. Look for and avoid wind drifts in unusual locations like lower on the slope and the sides of gullies.
Discussion
Avalanche and Snowpack Discussion
The only avalanche activity reported in the Snoqualmie Pass area Monday were loose wet avalanches that failed as the sun heated the recent snow.
In other zones, human triggered avalanches were reported Sunday and Monday. Many of these avalanches failed on a layer of buried surface hoar from December 26. Currently, we do not have any reports of this layer in the Snoqualmie Pass area. That doesn’t mean it isn’t there. You would be most likely to find a layer of buried surface hoar further east in the zone or at higher elevations, where the rain did not destroy it. If you find evidence of this layer, please let us know by submitting an observation.
12/31/18: Remotely triggered persistent slab avalanche in the Crystal backcountry.Â
If you use the nice weather to travel to higher elevations or into more remote areas take time to stop and observe the snow. Due to stormy weather we have not received any information from higher elevations in quite some time. Â
Snowpack Discussion
New Regional Synopsis Coming Soon
Avalanche Problems
Wind Slabs
Wind slabs formed over the weekend are gaining strength, but have not fully healed. Backcountry travelers and local professionals reported finding wind slabs in unusual locations such as low on the slope, and in areas often wind-stripped. You may still trigger wind slabs on convex rollovers, near the sides of cross-loaded gullies, and on wind drifted snow well below ridgeline. Use visual clues such as uneven snow surfaces, fresh cornices, and snow drifts to identify and avoid wind loaded slopes.
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