Avalanche Forecast

Issued: Mar 7th, 2013 4:00PM

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

chris gooliaff, Parks Canada

Banff Yoho Kootenay.

Extra caution advised in areas where the storm slab overlies a weak, faceted base (east of the Divide and near ridge crests).

Summary

Weather Forecast

Tomorrow and Saturday, mainly sunny except morning overcast/broken cloud over the southern regions. Freezing level to remain below 1200m, with alpine high's up to -7*. Winds light from the NW.

Snowpack Summary

The storm snow from last weekend continues to strengthen as a unit, with no obvious shears within it. It also seems to be bonding reasonably well to the underlying snow surfaces. However, in areas of thinner snowpacks (east of the Divide) and on steeper, southern aspects, the storm slab remains touchy and human triggering to size 3 is possible.

Avalanche Summary

Yesterday, a group of skiers remotely triggered, from 100m away, a size 3 slab near Dolomite Peak. They reported it failed on a S aspect and the crown was up to 2m thick. A field team behind the Lake Louise ski area noted several whumph's along open, tree-line features, and as a result, skied conservatively with little confidence in open slopes.

Confidence

Problems

Storm Slabs

The storm slab is becoming more cohesive as a layer and bonding to older surfaces. While this is good in areas of a deeper snowpack (west of the Divide), this will continue to create touchy slabs east of the Divide and in thin, weak areas.

Avoid convexities or areas with a thin or variable snowpack.Choose conservative lines and watch for clues of instability.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Mar 8th, 2013 4:00PM