Avalanche Forecast

Issued: Apr 11th, 2013 4:00PM

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

chris gooliaff, Parks Canada

Banff Yoho Kootenay.

It will feel wintery the next few days, with continued storms piling into us from the west. Danger ratings will increase during the peaks of each storm wave.

Summary

Weather Forecast

Clear skies should greet us tomorrow morning. Then another storm is lined up to pass through the forecast region Friday evening, delivering 10-15cm of snow with moderate westerly winds and freezing levels below 1300m.

Snowpack Summary

We received 10-15cm overnight, accompanied by moderate to strong SW winds. This will have developed into soft slabs in the alpine. Expect the slabs to be touchy for the next day or two. These slabs overlay 10-30cm of previous storm snow, which rest on suncrusts on solar aspects and facetted snow on polar aspects.

Avalanche Summary

Touchy soft slabs in the Lake Louise area and up highway 93N were reported in the immediate lees of ridgecrests. Slabs were on average 10-15cm thick, but in some cases up to 30cm thick.

Confidence

Forecast snowfall amounts are uncertain

Problems

Storm Slabs

Isolated soft slabs in the immediate lee of alpine features were reported in the Lake Louise area, as well as up 93N. 10-15cm thick slabs were touchy and propagating upwards of 20m from skiers/riders.

Avoid lee and cross-loaded terrain near ridge crests.Excellent conditions on sheltered Northerly aspects.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Dry

Fast sluffing of the storm snow on underlying crusts was reported in the Sunshine area today. This is a definite concern for skiers and climbers in gully/couloir features.

Be very cautious with gully features.Be cautious of sluffing in steep terrain.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

The combination of westerly winds, new snow, and higher humidity values has allowed some rapid growth of cornices along ridge-line features. These will be touchy if the strong, spring sunshine hits them Friday morning.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 12th, 2013 4:00PM