Avalanche Forecast

Issued: Mar 7th, 2012 8:10AM

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

Sylvia Forest, Parks Canada

Glacier.

Very tricky conditions exist. Large amounts of storm snow over several very weak layers are responsible for many large avalanches in the past 24 hours. This is a widespread cycle which is not yet over. Conservative route selection is advised.

Summary

Problems

Storm Slabs

Since last Friday, over 1m of snow has fallen. Temps rose through the storm forming a cohesive "upside down" slab, with moist snow below 1500m. Temps dropped overnight, tightening this slab and forming a crust at lower elevations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 3

Persistent Slabs

The Feb surface hoar layers are over 1.5m deep. Overloaded by the storm they produced very large avalanches. Avalanches are stepping down to these layers. Cornices have grown, and are becoming brittle, creating the potential for large triggers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 4

Wind Slabs

High S winds are producing windslabs and deep drifts on open slopes at all elevations. Wind loading has rapidly increased the load on persistent weak layers, which will take time to adjust. The weight of a skier may be all they need to avalanche.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

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