Avalanche Forecast

Issued: Dec 6th, 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.

Freezing levels are forecasted to rise to 3000m tomorrow. Forecasters are uncertain how this will impact the Oct 31 layer and avalanche hazard in general. Ice climbers should avoid climbing under start zones.

Summary

Weather Forecast

The freezing level is forecasted to climb to 3000m by midday on Thursday. Clear skies and light NW wind are accompanying the rise in freezing levels.

Snowpack Summary

Surface hoar up to size 5 has now formed on the surface. Below 2500m, 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 is a facet layer above 2500m and a crust below.

Avalanche Summary

No avalanches were observed or reported today.

Confidence

Freezing levels are uncertain on Thursday

Problems

Persistent Slabs

Natural avalanche activity has tapered however, shallow alpine areas warrant caution. Also, forecasters are uncertain as to how the Oct 31 layer will react to rising freezing levels on Thursday.

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

Possible

Expected Size

1 - 3

Wind Slabs

Recent moderate to strong winds have created variable windslabs in exposed alpine areas along the divide. These are mostly stubborn, but because they are of variable stiffness.

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.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 7th, 2017 4:00PM