Avalanche Forecast

Issued: Mar 16th, 2012 4:00PM

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

mike.koppang, Alberta Parks

Kananaskis.

An additional 20-25cm of snow over the past 24hrs will keep avalanche danger at HIGH in Alpine terrain. Conservative terrain choices and route selection are good ideas at this time.

Summary

Confidence

Good

Weather Forecast

Snowfalls to continue overnight and begin to taper off in the morning. Winds are expected to become more southerly and moderate and alpine temperatures will likely hover around -7C.

Avalanche Summary

No new observations due to limited visibility.

Snowpack Summary

Up to 25cm of recent HST at treeline over the past 24hrs. Now up to 40cm of snow is overlying the March 10th temperature crust and 110-150cm overlying the Valentines day surface hoar / Facet interface. Moderate sudden planar sheers overlying the March 10th crust and moderate sudden planar sheers also persist on the valentines day surface hoar. Propogation Saw test on a SE aspect at 2200m 30/110 END, indicating that propogation is likely on the Valentines day surface hoar layer.

Problems

Storm Slabs

Storm slabs are being encountered in open terrain up to 50cm thick. Sheers are being noted within the storm snow on northern aspects as well as on the march temp crust on solar aspects. Storm slabs can easily step down to the Valentines day layer.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 6

Persistent Slabs

Surface hoar buried up to 150cm continues to be a major concern in the snowpack. A dense slab now sits on top of this layer. Avalanches in the upper snowpack will likely step down to this layer causing a destructive avalanche.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 6

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

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

Expected Size

3 - 7

Valid until: Mar 17th, 2012 9:00AM