Avalanche Forecast

Issued: Feb 12th, 2017 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Touchy conditions continue. Very cautious route-selection is advised as human-triggering is a very real possibility. Also, keep an eye out for solar-triggering as the air temps are warm and the solar radiation is significant.

Summary

Confidence

High -

Weather Forecast

A ridge of high pressure has pushed into the region and will bring generally clear skies. Winds will be moderate to strong from the West. Alpine temperatures will climb to near +1 C, with freezing levels reaching 2000m. Tuesday and Wednesday will be a bit warmer before a slight cooling trend on Thursday.

Avalanche Summary

A group of skiers remotely triggered a size 2.0 avalanche near Black Prince today on an East aspect at 2200m. The slab was approximately 80cm deep and failed in the basal weak layers. There was nobody buried. In addition, a natural avalanche cycle continued today with avalanche activity up to size 3.0 in lee and cross-loaded terrain. A few of these avalanches initiated in the upper snowpack and then steeped down to the Dec 18th persistent weak layer once they reached the Treeline elevation band.

Snowpack Summary

Wind slabs dominate the Alpine and Treeline elevation bands. These slabs are found on all aspects, but the most recent loading pattern is from the SW loading up traditional lee and cross-loaded terrain and starting to strip windward slopes in the Alpine. As can be expected, the wind has helped the cornices grow and in some cases these have fallen off and started avalanches within the recent wind slabs. Below Treeline still has a distinct "upside down" feel to it due to the weak mid-pack. Whumphing is widespread and can propagate a long ways through the weaker layers. Think of this as you approach overhead terrain.

Problems

Wind Slabs

Wind slabs are everywhere, but the most recent loading is onto typical lee and cross-loaded features. The slabs are 50-60cm thick and are sitting on a variety of surfaces. These slabs are very sensitive to human-triggering.

Avoid cross loaded slopes at or above treeline.Avoid freshly wind loaded features.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

2 - 3

Cornices

Cornices are large and relatively new to the scene. Expect them to fail easily, especially as it warms up.

Give cornices a wide berth when travelling on or below ridges.Pay attention to overhead hazards like cornices which could easily trigger deep slabs.

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

Elevations: Alpine.

Likelihood

Very Likely

Expected Size

2 - 3

Deep Persistent Slabs

Many avalanches have stepped to this layer. Very large avalanches can be expected if this layer is involved. Large triggers(cornices) may wake this layer up.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 4

Valid until: Feb 13th, 2017 2:00PM