Avalanche Forecast

Issued: Jan 30th, 2017 3:29PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Another wave of cold weather on Tuesday and Wednesday will do nothing to improve the basal facets. Caution is advised in steep terrain as dense wind slabs overlie these weak base layers.

Summary

Confidence

High -

Weather Forecast

Tuesday will be a mix of sun and cloud with a high of only -18 °C. Winds will be light from the North, but will feel brisk! The cold weather hangs around for a couple of days. There is no precipitation expected in the near future.

Avalanche Summary

A Mountain Information Network (MIN) report was submitted yesterday sharing a close call by a party ski-touring in the Hero's Knob area. The remotely triggered a size 2.0 slab avalanche from 100m away. This occurred at approximately 2300m on a SE aspect. The slab was reported as 80cm thick, so it is quite possible that the failure plane was the Dec 18th persistent weak layer. See the MIN posting for more information by zooming in on the blue flag in the Hero's Knob area.

Snowpack Summary

Wind slabs are widespread in lee and cross-loaded features in the Alpine and in open areas at Treeline due to recent extreme westerly winds. These slabs sit on a weak and faceted mid-pack and basal layers. The snowpack at lower elevations remains shallow, weak and facetted and only supports the weight of a skier on previously established paths.

Problems

Persistent Slabs

If this layers if triggered, there is a likelihood of entraining the entire snowpack with it causing a large avalanche.

Avoid cross loaded features.Avoid unsupported slopes.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Deep Persistent Slabs

The big concern is that if anything gets triggered within the snowpack, then the avalanche will step down to the weak basal facets and involve the entire winter's snowpack.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Wind Slabs

Recent extreme westerly winds have created thin wind slabs to add to the existing wind slabs already out there. It is possible to trigger a smaller surface slab that could then step down to a deeper weak layer.

Avoid steep lee and cross-loaded featuresIf triggered the wind slabs may step down to deeper layers resulting in large avalanches.Be careful with wind loaded pockets while approaching and climbing ice routes.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Jan 31st, 2017 2:00PM