Avalanche Forecast

Issued: Mar 6th, 2012 9:59AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Wind Slabs, Storm Slabs and Persistent Slabs.

istorm, Avalanche Canada

South Rockies.

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

Until yesterday the weather story was all about snow with the last storm starting warm and finishing cold. Monday overnight a cold front came through. Looking forward the story for Wed & Thurs is sunshine - warm temperatures and SOLAR WARMING. Freezing overnight. Moderate NW winds. Friday becoming cloudy, maybe flurries ahead of the next forecast system.

Avalanche Summary

Tuesday reports are of solar triggered avalanches on sunny slopes (small and loose). Professionals were successfully & intentionally triggering small avalanches during control work in the new snow.

Snowpack Summary

20 to 50 cm of recent storm snow reported from the regions. Feb. 09 surface hoar is now down between 40 & 100cm. The depth varies throughout the region. This weak layer continue to perform and snowpack tests continue to show sudden moderate failures on this interface. The weekend's strong winds and mild temperatures formed the upper snowpack into a more cohesive slab. Lingering concern remains for basal facets, particularly in shallower snowpack areas with steep, rocky start zones. I suspect windslabs are developing with the forecast wind and recent snow.

Problems

Wind Slabs

Wind slabs fueled by gusty NW winds and new snow will be a widespread issue in wind exposed terrain.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Storm Slabs

New snow should bond well to the old snow surface, but be careful with convex rollers and unsupported slopes where the chances of triggering an avalanche are increased.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

Continued snowfall Monday night may be enough to wake up the Feb. 08 SH. Avalanches failing on this layer have the potential to be large and destructive.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 6

Valid until: Mar 7th, 2012 8:00AM