Avalanche Forecast

Issued: Dec 8th, 2012 4:00PM

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

Brad White, Parks Canada

Banff Yoho Kootenay.

Winds Monday with a warm storm may bump the danger rating. JBW

Summary

Weather Forecast

A warm Pacific push will bring cloudy skies and some precipitation for Sunday. On Monday the cold arctic air will move over the region and temperatures will drop. Winds are forecasted to increase to strong from the west on Sunday.

Snowpack Summary

Generally a well settled snowpack with some resistant planar shears related to the recent storm snow in the upper 40 cm. The Nov. Rain crust is approximately 30- 40 cm off the ground and is showing variable results. Good coverage and strength for early December.

Avalanche Summary

No new avalanches observed. On a flight today over the Wapta and Vermilion, several large size 2.5-3 full depth releases were observed that were approximately 3-4 days old. We suspect these failed on the Nov. crust.

Confidence

Wind speed and direction is uncertain on Monday

Problems

Wind Slabs

Soft to hard wind slabs can be found on lee and cross loaded slopes at and above treeline. Triggering is still possible on the right slope.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

Isolated deep slabs have been noted every few days over the last month. Some of these have been explosive triggered and some natural, all failing near the ground on Nov 6 rain crust or glacial ice. There is still a concern for human triggering.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Dec 9th, 2012 4:00PM