Avalanche Forecast

Issued: Feb 22nd, 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.

Some snow and wind are still forecast for Friday night. Watch local accumulations as this will dictate a rise in hazard at all elevations.

Summary

Weather Forecast

We still expect snow up to 20cm in the alpine Friday night with theÂ highest amounts along the divide and especially the Wapta.Â Expect strong SW winds over all regions. Another system is forecast on Sunday night.Â Steep areas below treeline and treeline W of the divide may go above a low hazard rating with a bigger snow load.

Snowpack Summary

2-9cm reported over last 24 hours in alpine regions. Some thin wind slab formation in immediate ridge top leesÂ This snow sits on top of previous wind slabs, both soft and hard, in alpine areas. Thin snowpack areas at all elevations are very weak and faceted, as well as most below treeline areas up to around 1900 meters.Â

Avalanche Summary

No activity reported today.Â 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

Forecast snowfall amounts are uncertain on Saturday

Problems

Wind Slabs

Wind slab formation, especially near ridge tops has been noted by a team on the Wapta. Expect these to be touchy within the next 24 hours.

Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Dry

Expect sloughing in steep gully terrain. Ice climbers should monitor this closely.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 2

Cornices

Cornices can provide the big trigger and entrain new wind slabs and underlying facets. Some of these cornices have been easily triggered in the last week.

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 23rd, 2013 4:00PM