Avalanche Forecast

Issued: Feb 28th, 2012 4:00PM

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

chris gooliaff, Parks Canada

Banff Yoho Kootenay.

A lot of settlement in the snowpack was heard and felt today on a ski tour in Kootenay. This kept us on well-supported, low consequence terrain. With small amounts of snow in the next few days, the tip-toeing around convex slopes will continue.

Summary

Weather Forecast

Snowpack Summary

Avalanche Summary

Confidence

Problems

Persistent Slabs

Stability tests on the Valentine layer in Kootenay today showed easy results, sudden planar, down 40-50cm. This is enough snow to create a large avalanche. This layer ranges from 20cm depth near Bow Summit, to 60cm near Sunshine and Yoho.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

Moderate winds in the past few days have also created thin, but stiffer wind slab conditions 25-35 cm deep on ridgetop lee terrain. These have been seen to step down to the Valentine layer. Several natural slides were observed off Mt Bosworth today.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

Near Bow Summit yesterday, we encountered moderate, sudden collapse shears on basal depth hoar. Steep, thin areas mainly E. of the divide will be prone. Lake Louise reported recent, isolated slides triggered on surface hoar which stepped to ground.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 29th, 2012 4:00PM