Avalanche Forecast
Issued: Mar 15th, 2012 10:25AM
The alpine rating is Storm Slabs, Wind Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Timing or intensity of solar radiation is uncertain
Weather Forecast
An unstable air mass will bring mainly cloudy skies and light snow amounts through the weekend, with freezing levels remaining at or near the valley bottom. If the sun shines through, solar radiation will be intense. Friday: Snow amounts 5-10 cm. Ridgetop winds moderate from the SW. Alpine temperatures -6. Freezing levels near 800 m. Saturday: Snow amounts near 5-10 cm. Cloudy skies. Ridgetop winds light from the SW. Freezing levels at valley bottom. Sunday: Mainly dry, cold conditions. Broken skies in the morning, sunny skies in the afternoon. Solar radiation may be intense. Freezing levels valley bottom.
Avalanche Summary
On Tuesday a natural avalanche cycle occurred up to size 3 on N-NE aspects. Cornices reached their threshold and triggered slopes up to size 2.5 below. On Monday, a skier was partially buried and two others escaped a size 2 slab on an east aspect at 1500m, which failed on a crust. Natural and skier-remote triggered avalanches to size 3 were also observed on a variety of aspects and elevations, some failing on the mid-February weakness. Crowns were up to 150cm deep. Every day of the last week, avalanches have been triggered either naturally, remotely or accidentally by backcountry travelers. Unsettled weather conditions continue. It may take several days for all this new storm snow to settle out. If the sun shines through in your local mountains; expect strong solar radiation, snowpack deterioration, and elevated avalanche danger.
Snowpack Summary
Stormy conditions continue! Over 1100-180 cm storm snow has fallen, accompanied by strong SW winds. Storm slabs and wind slabs continue to build. Cornices are large, some reaching threshold and triggering the slopes below. For the most part, the new storm snow is right side up (lower density snow on top) and easy to moderate shears exist within the upper meter. The additional weight of new storm and wind slabs may step down and trigger a deep weakness, formed in mid-February. Recent test results on this layer produced hard sudden planar results down 120cm in the snowpack (DTH24 SP dwn 120cm on FC/RG 0.5). Very large avalanches are possible, which could be remote-triggered, triggered mid-slope, and/or propagate into low-angled terrain.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Aspects: North, North East, East, South East.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 16th, 2012 9:00AM