Avalanche Forecast

Issued: Dec 1st, 2017 4:00PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

Natural activity has tapered off, but it's still early season and we don't have many alpine observations. We feel it is moderate by definition, but there is still potential to trigger something if you are getting into bigger terrain.

Summary

Weather Forecast

Light snow and lightly cooling temperatures are forecast.

Snowpack Summary

The main weakness to watch is the Oct 31 crust/facet layer located about 30cm above the ground that is producing moderate sudden collapse test results throughout our region. The crust is more prominent below ~ 2400m, and becomes a facet layer above this. New snow windslabs are common in the alpine.

Avalanche Summary

An avalanche was noted over Cascade Falls this morning.

Confidence

Problems

Persistent Slabs

Natural avalanche activity has tapered, but it is still possible to trigger a large avalanche in this layer. Slab avalanches have been most commonly triggered ~ 2400m where the Nov. 23rd crust fades out.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Wind Slabs

Up to 50cm of recent snow has been blown into windslabs in the alpine. These have been reactive to ski cuts, but are still soft and predictable at this point.

Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 2nd, 2017 4:00PM