Avalanche Forecast
Regions: Olympics.
Watch for isolated wind slabs in exposed terrain, especially above treeline on Tuesday.
Detailed Forecast
Mild and cloudy weather should be seen in the Olympics Tuesday.Â
Watch for isolated wind slabs in exposed terrain, especially above treeline. Look for signs of wind transported snow such as uneven snow surfaces, fresh cornices, and snow drifts. Each of these observations are signs that the wind has redistributed snow in the area. Identify and avoid wind loaded terrain features.
Wind slabs can be deceptively difficult to manage in the terrain. Take a moment and read our recent blog post by NWAC Pro Observer Jeremy Allyn on wind slabs.
Snowpack Discussion
Happy New Year from your friends at NWAC!
Mild weather Sunday and Monday has allowed the snowpack to continue to heal and gain strength following an active weather pattern this past week.
SW winds Friday night redistributed new snow forming shallow wind slabs on lee slopes at higher elevations. This resulted in a variety of snow surfaces including soft unconsolidated snow, wind scoured slopes, rain crust, and firm wind slabs.
The 12/16 mid-December crust can still be found 2-3 feet down within the snowpack.
Observations
NWAC pro observer, Matt Schonwald visited Hurricane Ridge on Friday, 12/29 and stressed that this is a different snowpack than the Cascades! He visited W-NW-N-NE aspects and found the 12/16 crust and 1-2 mm facets down 2.5 feet. Several PST tests failures, self-arrested, but propagated through most of the column along the 12/16 layer. This PWL will mostly likely be found below ridgelines and will have to be watched moving forward.Â
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: North, North East, East, South East, West, North West.
Elevations: Alpine.
Likelihood: Unlikely
Expected Size: 1 - 1