Avalanche Forecast

Issued: Mar 11th, 2012 5:00PM

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

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

Up to 20cm of new snow and strong wind is expected by Tues morning, adding more load to an already debilitated snowpack. Given the fragility of the Feb 14 layer, expect to see large and destructive avalanches running far and fast.

Summary

Weather Forecast

Snowpack Summary

Avalanche Summary

Confidence

Intensity of incoming weather systems is uncertain on Tuesday

Problems

Persistent Slabs

A slab overlies the Valentine surface hoar down 60-100 cm. Natural activity with this layer is subsiding, however, it is still prime for human triggering. In test pits today, the layer was prominent and producing results in the moderate range.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 4

Deep Persistent Slabs

Slabs starting on the Feb 14 layer can step down, triggering deep slabs. When triggered, these large and destructive avalanches will slide on basal facets close to the ground. Fracture lines could be up to 200cm deep with wide propagations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Mar 12th, 2012 5:00PM