Avalanche Forecast

Issued: Jan 20th, 2018 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

We seem to be near the tipping point for increased avalanche activity. Make conservative terrain choices.

Summary

Confidence

High -

Weather Forecast

Saturday will be cloudy with sunny periods and isolated flurries. Alpine temperature are expected to reach a high of -11 °C. Ridge top winds will be out of the southwest at 45 km/h. The pattern remains for the next few days.

Avalanche Summary

A few new size 2 slab avalanches were observed in the past 48hrs. These avalanches occurred in steeper Treeline areas failing down 30-40cm. In addition a few small loose dry avalanches occurred today in steep Alpine and Treeline terrain.

Snowpack Summary

A few cm's of new snow overnight has added to the recent 20cm over the past few days. Winds have been strong during the snowfalls, which has created extensive wind slabs in the Alpine and open areas at Treeline. At 2250m and below there are now 3 layers of buried surface hoar, which is very unusual for the Rockies. These are referred to as the Jan 18th, Jan 6th and Dec 15th surface hoar layers, down 25, 50 and 100cm respectively. Snowpack stability tests today 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 crust layers are still on our radar, but still do not appear to be reactive. The question is when these layers will become a problem.....

Problems

Wind Slabs

Strong winds and warm temps have combined to build widespread wind slabs in the Alpine & open Treeline areas. Wind loading continued today, so these slabs will be sensitive to human triggering and natural avalanches are possible.

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 - 2.5

Persistent Slabs

Forecasters are tracking 3 buried layers of concern (click on "Details" for more), which are variable in their distribution in both elevation and aspect. Carefully evaluate these layers before committing to a piece of terrain.

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 - 2.5

Valid until: Jan 21st, 2018 2:00PM