Avalanche Forecast

Issued: Nov 30th, 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.

ian jackson, 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

A westerly flow will bring consistent, but light precip amounts this week. 5- 10 cm per day with higher amounts in the north of the region. Winds will be light to moderate from the west in the alpine and freezing levels will be below valley bottom.

Snowpack Summary

25 cm of settled snow over the past week has been blown into reactive windslabs in the alpine. The main weakness to watch is the Oct 31 crust/facet layer located about 30cm above the ground which is producing moderate sudden collapse test results. This layer is a temperature crust below ~ 2400m and a facet layer above this.

Avalanche Summary

No avalanches were reported or observed today.

Confidence

Due to the number of field observations

Problems

Persistent Slabs

Natural avalanche activity has tapered, but it is still possible to trigger this layer if you hit it in the right spot. We are most concerned about this above ~ 2400m where the Nov. 23rd crust fades out.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.

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 1st, 2017 4:00PM