Avalanche Forecast
Issued: Feb 23rd, 2012 8:35AM
The alpine rating is Wind Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Good
Weather Forecast
Friday: Moderate snow beginning in the morning - 5-15cm. The freezing level (FL) is around 500-800m. Ridge top winds should be moderate from the SW. Saturday: Continued moderate snowfall - an additional 10-20cm overnight and through the day. FL 800-1000m. Winds should ease to light from the west. Sunday: Unsettled conditions with convective flurries likely. FL drops to valley bottom. Winds are light and variable.
Avalanche Summary
A large natural avalanche cycle occurred on Wednesday. Slab avalanches were reported up to Size 3.5 on all aspects and at all elevations. There were also numerous reports of skier triggered and remotely triggered avalanches on a variety aspects. The potential for human triggered avalanches remains high in all terrain over 30 degrees.
Snowpack Summary
Moderate west-northwest winds have created weak wind slabs in exposed alpine and treeline terrain. Up to 70cm of new snow now sits on the February 16th Surface Hoar layer and is slowly settling into a cohesive slab. The February 8th weakness is now down 80-100cm. This layer is a combination of weak layers: In most locations it marks a widespread surface hoar layer. On steep south & west facing aspects a sun crust that formed during the drought was also buried on Feb. 8th. This crust likely has a bit of faceting below it too, meaning that most terrain in the region has a weak layer 40-60cm under the snow surface. These buried weaknesses have made conditions very tricky with the potential for triggering in lower angle terrain and from a distance. It is should be noted that large cornices remain widespread throughout the region and may fail as temperatures fluctuate over the next few days.
Problems
Wind Slabs
Aspects: North, North East, East, South East, South.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 24th, 2012 8:00AM