Avalanche Forecast

Issued: Mar 6th, 2013 8:03AM

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

sylvia forest, Parks Canada

Glacier.

Large skier triggered avalanches are still possible! Be aware of the terrain you are in, look for overhead hazards. Be aware of the effects of solar radiation today.

Summary

Weather Forecast

A weak upper ridge will linger over the area today, bringing mostly sunny skies. A weak low will move through late this afternoon or evening, bringing cloud and a chance of flurries. Clearing skies are again expected for Thursday. Watch for locally strong solar radiation on solar aspects.

Snowpack Summary

Last weeks' storm snow has settled out rapidly over the past two days. Below treeline, a rain crust and substantial tree bombs have created treacherous travel in some places. In the alpine, soft slabs overly the Feb. 12 PWL, now down over a meter and continues to be a concern, especially on solar aspects. Wide propagations are still possible.

Avalanche Summary

Natural avalanche activity has decreased however large avalanches are still possible. We are entering a period of "low probability, high consequence" avalanche behavior, in which the likelihood of triggering is less than it was during the storm, but the chance that a skier can trigger a very large avalanche is still very possible. See photo:

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Storm Slabs

The storm slab has settled considerably over the past 2 days, but remains a concern due to the potential for wide propagations and step-down to the Feb 12 PWL. Solar aspects and lee pockets are of particular concern.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Be wary of slopes that did not previously avalanche

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Persistent Slabs

The Feb 12 PWL continues to be a concern. During the last storm cycle several avalanches "stepped" down to this layer. It will remain a problem for some time.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Cornices

Cornices have grown very large and unsupported. They are increasingly likely to fail, providing a trigger for large avalanches. Northerly winds have created reverse loading in some areas.

Avoid areas with overhead hazard.Avoid steep slopes below cornices.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Mar 7th, 2013 8:00AM