Avalanche Forecast

Issued: Mar 24th, 2015 4:00PM

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

Lisa Paulson, Parks Canada

Banff Yoho Kootenay.

Good skiing on North aspects. 10-20 cm blanket the Wapta with little wind effect on regular travel routes. Winds pick up Thursday and freezing levels rise causing the hazard to rise as we approach the weekend.

Summary

Weather Forecast

Expect clear skies and a good freeze tonight. Very light flurries move in to the region Wednesday and winds will remain generally light from the West with some gusts. Snow picks up for Thursday, along with the wind, and rising freezing levels to 2600 m by Friday. By Sunday, accumulations may be up 10 cm.

Snowpack Summary

Convective cells have dropped 10-20 cm's with light winds over the last few days. Wind slabs exist in isolated immediate lee features and open areas in the alpine and sit on a variety of hard surfaces. The base of the snowpack is made up of facets and depth hoar and remains weak. Below tree line, snow is isothermal in the afternoons.

Avalanche Summary

Local ski hills reported a few small explosive controlled windslabs in steep unsupported terrain over the past 2 days. Temperatures remained cool today - no pinwheeling observed and crusts remained intact down to 1900 m.

Confidence

Problems

Wind Slabs

Wind slabs up to 35cm can be found in the immediate lee features. Although there has been some improvement, they are sensitive to human triggering on features such as ridge crests, cross loaded gullies, and steep terrain features.

Use caution in lee areas. Recent wind loading have created wind slabs.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Deep Persistent Slabs

The lower half of the snowpack is weak due to the presence of basal facets and depth hoar. This layer has been dormant lately but may become more sensitive with the recent new snow load, especially in thin areas.

Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Mar 25th, 2015 4:00PM