Avalanche Forecast

Issued: Jan 23rd, 2018 3:25PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Natural avalanche activity continued today in specific terrain. There are numerous buried layers of concern. Take the time to evaluate these before making terrain decisions.

Summary

Confidence

Moderate -

Weather Forecast

Wednesday will be cloudy with light flurries and accumulations between 5 and 10cm. Temperatures will reach -5 Â°C. Winds will be strong from the southwest. Not much snow is expected from the occasional flurries on Thursday and Friday.

Avalanche Summary

Several slab avalanches have occurred in the past 24 hours up to size 2.5. These slides occurred in steep Alpine terrain on north, east and south aspects. Fracture depths range from 40 to 80cm, corresponding with the Dec 15th interface in most cases. Yesterday a size 3.0 naturally triggered slab avalanche occurred on a steep north aspect in the Alpine and ran full path.

Snowpack Summary

A few cm's of new snow fell last night. With a week of very strong winds wind slabs are widespread in alpine and treeline terrain and have snuck themselves into open areas below treeline. Expect to find hard slabs in the alpine and a mix of hard and soft slabs everywhere else, except where the winds have stripped the snow down to bare rock. Cornices have grown significantly in the past few days and are now very large and looming. At 2250m and below there are 3 layers of buried surface hoar. These are referred to as the Jan 18th, Jan 6th and Dec 15th surface hoar layers, down 25, 50 and 100cm respectively. All of these layers appear reactive at the moment. The deeply buried November and October crusts are being tracked and may come alive in shallow snowpack areas.

Problems

Wind Slabs

Wind slabs are everywhere in the Alpine and at Treeline, except on windward aspects. Several recent avalanches have occurred associated with this problem.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Avoid steep lee and cross-loaded slopesAvoid freshly wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

Numerous buried weak layers are causing some concern at Treeline. Avalanche activity observed in the past 2 days initiated in the upper snowpack and then steeped down to the persistent slabs.

Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.Avoid convex rolls at and below treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Jan 24th, 2018 2:00PM