Avalanche Forecast

Issued: Feb 22nd, 2015 8:09AM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

There is still good skiing to be had on sheltered polar aspects. Watch out for reverse loaded slopes and keep an eye out for rising temps. PW

Summary

Confidence

Good

Weather Forecast

Tomorrow will see a mix of sun and cloud, but will be warming to near zero in the alpine. Freezing levels are expected to climb to 2200m. The winds will be light from the north.

Avalanche Summary

There were numerous skier initiated sluffs in steep(>40) terrain, but the sluffs were not running far and slowed to where the angle eased to 35deg. or less.

Snowpack Summary

The storm snow has settled dramatically on southern aspects due to solar effect, but up to 12cm of low density snow remains on the surface on polar aspects. There has been evidence of reverse loading wind effect at upper exposed treeline and alpine elevations and soft slabs have formed in the immediate lees of features at these elevations. A test pit today at treeline elevations showed the upper snowpack to be healing and gaining strength. The pit was in a sheltered area, but exposed areas at this elevation have seen some wind. The mid-pack is gaining strength but weak facetted grains still dominate the base of the snowpack. At 2400m there is a discernable crust on solar aspects and 2100m and below there is a crust on all aspects under the most recent snow.

Problems

Persistent Slabs

The previously formed wind slabs are still lurking under the latest snow. Keep an eye out for this in the alpine and exposed treeline elevations on steeper features.

Choose well supported terrain without convexities.>Watch for areas of hard wind slab in steep alpine features.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

Some of these have occurred due to reverse loading, from northerly winds. Slabs up to 30cm have been formed in the immediate lee of ridgelines.

Caution in lee and cross-loaded terrain near ridge crests.>Avoid travelling in areas that have been reverse loaded by winds.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

Keep an eye out for cornices as possible large triggers, especially when the sun comes out and the temps begin to rise. This basal weakness is still on our radar.

Be aware of the potential for large, deep avalanches.>Be aware of thin areas that may propogate to deeper instabilites.>Pay attention to overhead hazards like cornices.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 5

Valid until: Feb 23rd, 2015 2:00PM