Avalanche Forecast
Regions: Cascades - North West.
Identify and avoid wind loaded slopes above treeline where you may still be able to trigger avalanches Sunday. At all elevations non-avalanche hazards exist, such as slick snow surfaces where stopping a fall may be very difficult.
Detailed Forecast
Unstable snow can be found on wind loaded slopes above treeline. Another day of clear, cool weather with light winds will slowly allow these Wind Slabs to gain strength. Identify and avoid slopes where recent wind deposition has occurred. Fresh cornice, snow drifts, and uneven snow surfaces all indicate wind loading on nearby slopes.
No avalanche problems are expected near and below treeline Sunday. Avalanches are unlikely but not impossible. Always carry a beacon, shovel, and probe. Use appropriate travel techniques to minimize your exposure to avalanche terrain.
Other non-avalanche hazards exist. Glide cracks and firm snow surfaces may cause danger to backcountry travelers. Avoid steep icy slopes where stopping a fall may be very difficult.
Snowpack Discussion
A few inches of recent snow sits on top of a strong supportable crust layer. This crust layer extends in to the near treeline band and potentially higher. Sunny weather Saturday affected the recent surface snow on south aspects at all elevations.
Above treeline, as the snow was falling winds redistributed snow onto a variety of aspects. No recent observations have been reported from above treeline. Uncertainty exists within this elevation band.
Warm and wet weather the first week of February created a strong and consolidated mid and lower snowpack. There are no significant layers of concern in the snowpack at this time.
Observations
An avalanche professional in the Mt Baker backcountry Saturday reported winds transporting snow above treeline. Surface crusts were strong and supportable.
On Wednesday, NWAC Pro Observer Lee Lazzara was touring around Table Mountain. He found 2-6" of recent moist snow above a mostly strong snowpack with no lingering instabilities. He reported numerous glide cracks which could be dangerous, particularly if covered by fresh snowfall in the future.
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