Avalanche Forecast

Issued: Feb 21st, 2013 4:00PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

If the weather forecast comes to fruition on Friday, expect an increase in hazard through the weekend.

Summary

Weather Forecast

A fast moving low pressure system is forecast to give us 15-20cm and strong Westerly alpine winds starting sometime in the afternoon on Friday.Â Timing and intensity of this one is hard to predict, but expect worsening weather in the afternoon. The highest amounts are forecast for North and West of Lake Louise (Wapta region)

Snowpack Summary

Thin snowpack areas at all elevations areÂ weak and facetted, as well as most below treeline areas up to around 1900 meters.Â Previous storm snow has settled to approximately 10cm.Â This snow sit on top of wind slabs, both soft and hard, in alpine lee areas.

Avalanche Summary

No activity reported today.Â Avalanche control on Wednesday produced avalanches up to size 3.Â Cornices that were triggered provided enough of a rake to entrain all of the facets in the path, running to within 100m of the road on Mt. Whymper (Kootenay) and Mt. Dennis (Yoho).Â

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Friday

Problems

Wind Slabs

New wind slabs will be forming with forecast snow Friday afternoon, watch locally for building sensitivity to triggering.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Dry

Steeper slopes and gullies in the alpine will slough easily with any new snow load and wind over the already present facets. Ice climbers should monitor this closely.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 2

Cornices

Cornices triggered facet avalanches on Wednesday, see avalanche discussion

Pay attention to overhead hazards like cornices.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 22nd, 2013 4:00PM