Avalanche Forecast

Issued: Nov 30th, 2013 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 Loose Dry.

conrad janzen, Parks Canada

Banff Yoho Kootenay.

Avalanche hazard will begin rising as the new snow arrives on Sunday afternoon and Monday. Keep a close eye on local snowfall amounts and winds. CJ

Summary

Weather Forecast

Moderate snowfall is forecast to begin by mid-day on Sunday with 5-10cm of new snow by Sunday evening accompanied by strong West winds. An additional 5-10cm is forecast for Monday before the cold, dry arctic air arrives on Tuesday.

Snowpack Summary

On lee features in the alpine the snowpack consists of wind slabs over a weak mid-pack with a very weak base of facets. The Oct 27 crust on N-NE aspects in the alpine is breaking down, but is still a sliding layer near ground. On average at treeline there is 70 cm of snow, barely blanketing the rocks and stumps.

Avalanche Summary

No new avalanche activity over the last 48 hours. Expect sluffing to begin as the new snow arrives on Sunday.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Wind Slabs

Some lingering wind slabs over facets or the October crust still exist in the alpine on lee slopes. With the new snow and moderate to strong W winds, expect new wind slabs to form quickly over the next two days.

Avoid freshly wind loaded features.The recent snow may now be hiding windslabs that were easily visible before the snow fell.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Dry

Ice climbers in particular should watch for rapid wind loading and sluffing in steep alpine terrain as this next storm arrives on Sunday afternoon. Watch local snowfall amounts carefully and plan to be off of exposed terrain early.

The volume of sluffing could knock you over; choose your climb carefully and belay when exposed.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 1st, 2013 4:00PM