Avalanche Forecast

Issued: Jan 22nd, 2018 3:24PM

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.

A few large avalanches have occurred in the past 24hrs. Dangerous avalanche conditions exist at upper elevations.

Summary

Confidence

Moderate -

Weather Forecast

Tuesday will be cloudy with sunny periods and isolated flurries. Alpine temperature will be near -9 °C. Winds remain strong out of the SW. Wednesday may bring a few cm's of new snow.

Avalanche Summary

Avalanche activity has increased in the past 24 hours. A size 3.0 naturally triggered slab avalanche occurred in the past 24 hours on a steep north aspect in the Alpine. This avalanche is expected to have run on the Dec 15th interface, and the slide ran full path. In addition, a couple of size 2.0 slab avalanches occurred on steep East aspects at Treeline. These slabs appeared to initiate on the Jan 6th interface and then step down to the Dec 15th interface with fracture depths up to 80cm.

Snowpack Summary

Several days of very strong winds has led to widespread wind slab conditions in the Alpine and open areas at Treeline. These are found on all aspects except west, where the winds have stripped the windward slopes down to bare rock. At 2250m and below there are now 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. Recent snowpack stability tests indicate that all these layers are reactive, with the Jan 6th and Dec 15th layers the most concerning as there is now sufficient overlying slab to be an avalanche problem. The November and October crusts deeper in the snowpack are being tracked but remain inactive at the moment.

Problems

Wind Slabs

Wind slabs are everywhere in the Alpine and open areas at Treeline, except on windward aspects. Avalanche activity increased today in steep lee and cross-loaded terrain.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

Forecasters are tracking 3 buried layers of concern (click on "Details" for more), which are highly variable in their distribution. Avalanche activity observed today initiated in the upper snowpack and then steeped down to the persistent slabs.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Jan 23rd, 2018 2:00PM