Avalanche Forecast

Issued: Mar 8th, 2013 3:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Storm Slabs, Loose Dry and Cornices.

burke.duncan, Alberta Parks

Kananaskis.

Avalanche Danger at Treeline may be subject to an increase depending upon just how severe the chinook winds forecast over the next 48 hours become. Watch out for daytime heating influences that will affect both ski quality and safe travel.

Summary

Confidence

Good

Weather Forecast

Little to no new snow expected over the weekend. Winds will pick up in intensity and we will see more redistribution of last Sundays's storm snow occurring. Temperatures have already begun a steady rise and we are seeing solar influences at treeline and below. A strong upper ridge of high pressure will keep skies mainly clear with temps above normal values.

Avalanche Summary

Widespread sluffing of loose dry storm snow is the most common avalanche observation again Friday. In a few areas the sluffs are entraining enough volume to be considered Size 2's. No new slab avalanche activity was observed.

Snowpack Summary

Below treeline surface layers in solar exposed areas are becoming moist with daytime heating and a thin crust has formed. Steep southerly aspects at higher elevations are also suffering from some solar exposure as well. Fracture characteristics exhibited in a hasty profile on a 30 degree north facing aspect at treeline showed a 'progressive compression' in a 30cm storm snow layer. The storm snow layers appear to be bonding well to the old surface layers. Larger and more fragile cornices are likely to form.

Problems

Storm Slabs

Snow from the past several days is rapidly settling out. Slab development is present in lee and cross-loaded terrain. Natural avalanche activity declined through the week but prime conditions for human triggering remain.

Assess start zones carefully and use safe travel techniques.>Avoid lee and cross-loaded terrain near ridge crests.>Be aware of thin areas that may propagate to deeper instabilites.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 5

Loose Dry

Recent snowfall and light/moderate winds has led to sluffing from steep terrain on all aspects at all elevations. This pattern is continuing with steady light snowfalls expected to continue until Friday AM.

Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Cornices

Cornices growth is likely to accelerate as winds increase over the weekend. Cornice failures earlier in the week triggered slab avalanches up to Size 3 on the slopes below.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 5

Valid until: Mar 9th, 2013 2:00PM