Avalanche Forecast

Issued: Dec 4th, 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.

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

The wind did not pick up as expected on Monday, however, be watchful for isolated wind slabs in lee areas. Activity has subsided on the Oct 31 layer but forecasters are still watching it closely.

Summary

Weather Forecast

A strong high pressure system is building in the region. Temperatures are expected to be seasonal with light to moderate wind from the West.

Snowpack Summary

Above 2500m, 60cm of snow from last week is being blown into soft windslabs in isolated areas. Below 2500m, up to 30 -50 cm of snow lies over the Nov 27th and Nov 23rd crusts. Both of these now overly the Halloween crust/ facet layer that sits 30-50cm above the ground. This lower layer presents as a facet layer above 2500m and as a crust below.

Avalanche Summary

No avalanches were observed or reported today.

Confidence

Wind speed and direction is uncertain on Wednesday

Problems

Persistent Slabs

Natural avalanche activity has tapered, but concern remains for human triggering on the weak snow on this layer. Previously, slab avalanches have been triggered above ~ 2400m where the Nov. 23rd crust fades out. Shallow alpine areas warrant caution.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Wind Slabs

Up to 50cm of recent snow is available for transport TL and above.

Use caution in lee areas. Recent wind loading has created wind slabs.Watch for surface cracking and stiffer surface layers of snow. Avoid wind loaded terrain.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 5th, 2017 4:00PM