Avalanche Forecast

Issued: Nov 18th, 2017 4:26PM

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

Alberta Parks matt.mueller, Alberta Parks

The wind is changing the snowpack drastically. Watch for new windslabs where there is still snow. Conservative terrain is a good idea while we wait for the snow to stabilize. See avalanche discussion for recent avalanche activity.

Summary

Confidence

High -

Weather Forecast

Periods of snow starting around noon. 13 cm expected. The winds will continue to howl with SW ridgetop winds over 60km/hr. Daytime highs will be -8, but expect it to feel much colder with the wind. More snow is expected early next week as well as continued high winds.

Avalanche Summary

There were 2 observations today, with one of them being a serious involvement with a party ascending a slope. Details:1)No involvement: Sz 2, S asp, a heavily crossloaded alpine feature that ran quite far. Unsure of trigger, but suspect natural1) Involvement: While boot packing, a party triggered a sz 2,  steep gully feature. SW aspect, approx 2650m alpine feature. The failure plain was within the many windslab layers.

Snowpack Summary

Wind! We haven't had any new snow, but we have had plenty of wind blowing existing snow around. Treeline and alpine areas now  have widespread wind slabs on all easterly aspects. Given the gusty nature of the wind, expect "laminated" or layered wind slabs with no distinct or predictable failure plain. These short term instabilities will stabilize eventually, but for now they should at the front of your mind. Alpine gullies are especially concerning right now. The halloween crust is still lurking below. The burial depths may will vary with this ongoing wind event .

Problems

Wind Slabs

An icon showing Wind Slabs
There has been heavy wind loading in most alpine areas. Expect dense windslabs in any area that has managed to hold snow. These are easy to trigger and will run far. Treeline has a similar issue, but the slabs will be less dense.
Avoid lee and cross-loaded terrain near ridge crests.Be careful with wind loaded pockets while approaching and climbing ice routes.Avoid freshly wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Valid until: Nov 19th, 2017 2:00PM