Avalanche Forecast
Issued: Feb 1st, 2013 9:15AM
The alpine rating is Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Poor - Due to variable snowpack conditions
Weather Forecast
Saturday: No significant precipitation expected. Alpine temperatures near zero degrees with freezing levels rising to 1800 m. Â Ridgetop winds will blow moderate from the South.Sunday: The brunt of the frontal system will take effect, bringing light precipitation accompanied by strong SW ridgetop winds. Alpine temperatures near -4.0 and freezing levels falling to 700 m. Â Monday: Cloudy skies with light precipitation. Ridgetop winds will blow light from the SW. Alpine temperatures dropping to -9.0 with freezing levels lowering to valley bottoms.
Avalanche Summary
Natural sluffing from steep terrain features. On Thursday, a remote triggered slab avalanche size 2.0 initiated 50 m away from the skier at treeline elevation. Another report of a size 2.0 slab avalanche (skier triggered) also occurred. Both incidents were at 1200-1300 m on North aspects with crowns 50-60 cm deep, 30-40 m wide, and running up to 150 m in length.
Snowpack Summary
Touchy wind slabs have built on lee slopes (N-SW) and behind terrain features likes ribs and ridges. Up to 50 cm of snow sits on a variety of old surfaces including old wind slabs, scoured thin slopes, crusts and surface hoar. This interface has shown reactivity to rider triggers, especially around treeline and below treeline elevations. Warmer temperatures have promoted some settlement and consolidated the recent snow into slab-like characteristics. With little observations from the field it's hard to get a good handle on how widespread this layer is. I stress the importance to dig down and test weak layers. Become familiar with the snowpack in your neck of the woods. The average snowpack depth at treeline is near 100 cm but remains quite inconsistent across the region. A strong mid-pack currently overlies a weak base layer of facets/depth hoar. Triggering of this basal weakness may still be possible from thin spots, rocky outcrops or under the weight of larger triggers such as cornice fall and larger amounts of new storm snow.
Problems
Wind Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 2nd, 2013 2:00PM