Avalanche Forecast

Issued: Mar 12th, 2012 4:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

More than 30cm of snow is expected through Tuesday with strong to extreme SW winds. A natural avalanche cycle will likely begin Tuesday morning. It is time to pull in the reins and avoid all avalanche terrain.

Summary

Confidence

Fair - Timing of incoming weather is uncertain

Weather Forecast

Heavy snowfall expected with strong to extreme winds. Freezing levels falling through the day.

Avalanche Summary

Few naturally triggered sluffs up to size 2.0 in steep lee terrain at alpine and treeline elevations.

Snowpack Summary

Up to 15cm new snow overnight. Extensive wind transport at all elevations. Hard slabs and soft slabs formed at alpine and treeline areas. Valentine's surface hoar buried up to 100cm and is still reactive to stability tests.

Problems

Storm Slabs

Recent snow and wind have formed thin wind slabs at treeline and above in lee and cross loaded terrain. These slabs are expected to grow significantly with the forecasted 30cm of snowfall on Tuesday and will become very touchy.

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 5

Persistent Slabs

Surface hoar buried up to 100cm continues to be a major concern in the snowpack. A dense slab now sits on top of this layer. Remote triggering is a real possibility. Several recent avalanches have stepped down to this layer.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 7

Deep Persistent Slabs

The weak basal facets and depth hoar have re-awakened. Large terrain features are areas of concern where a smaller slide could step down and trigger a very large avalanche with deep and wide propagation.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 7

Cornices

Cornices have grown significantly in the alpine. Failures continue to occur and have triggered avalanches up to size 3 on the underlying slopes. Give cornices a wide berth and stay well back from corniced ridge crests.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 7

Wind Slabs

Numerous layers of wind slab are prominent on lee and cross loaded features, and favorable weather conditions exist for continued slab formation. A failure in these slabs will likely step down to the surface hoar or the basal facets.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 6

Valid until: Mar 13th, 2012 9:00AM