Avalanche Forecast

Issued: Mar 12th, 2016 3:00PM

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

mike.koppang, Alberta Parks

Kananaskis.

Daytime warming persists. Windslabs sit on a variety of storm interfaces, solar and melt- freeze crusts. Be very cautious in terrain where these slabs are sitting on crusts as these windslabs will be quite touchy until temperatures cool off.

Summary

Confidence

Moderate - Wind speed and direction is uncertain

Weather Forecast

Mainly cloudy with scattered flurries with a few centimetres of snowfall. Temperatures in the alpine will be -4.0 with freezing levels forecast for 1600 meters for Sunday. Winds will be out of the southwest light to moderate with some gusts to 60km/h.

Avalanche Summary

Observations were limited today but the high freezing levels will have caused some pin wheeling and likely some loose wet avalanches from lower treeline and below treeline on steeper slopes. Forecasters were called out to a rescue today which terminated our trip to the Commonwealth area prematurely. There were some windslabs up to size 2.0 on the recently buried crusts and isolated natural or cornice triggered deep persistent slabs up to size 3.0 in Banff National Park.

Snowpack Summary

Moist snow exists today up to 2300 meters on all aspects and elevations. There is 15-25cm overlying the March 8th interfaces (melt-freeze crusts and sun crusts). The upper snowpack is settling rapidly with the mild temperatures. In the alpine and upper treeline, wind slabs have been developing over the past few days and extra caution will be required where the wind slabs overlie the March 8th crust interface. The January 6th facets interface is showing improvement but large avalanches up to size 2.5-3.0 are still occurring on the interface so it persists as a layer that is low probability/high consequence avalanche problem.

Problems

Wind Slabs

Windslabs are building in the alpine and tree line elevations and can be found in and around the lee of ridge crests and in cross wind affected terrain.

Avoid lee and cross-loaded terrain near ridge crests.>Avoid freshly wind loaded features.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Deep Persistent Slabs

The January 6th interface is still a big concern and although evidence from test profiles indicate improvement, we still have little trust in this layer. Shallow snowpack areas around moraine features or near ridge top where the winds have scoured.

Avoid convexities or areas with a thin or variable snowpack.>Carefully evaluate and use caution around thin snowpack areas.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Cornices

With the warm temperatures and winds, cornices will be tender and prone to failure for the remainder of the weekend.

Avoid steep slopes below cornices.>Choose regroup spots carefully.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Mar 13th, 2016 3:00PM