Avalanche Forecast

Issued: Jan 13th, 2012 9:17AM

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

Avalanche Canada mbender, Avalanche Canada

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

SATURDAY: Light to moderate amounts of snow in the overnight period Friday into Saturday with continued moderate accumulations throughout the day. Winds moderate to strong from the west and southwest. Temperatures gradually dropping as cold air invades from the north. SUNDAY: Light amounts of snow in the early part of the day and colder temperatures. Winds light to moderate from the north. MONDAY: Cold and clear throughout the day.

Avalanche Summary

Recent activity seems to be isolated to WSL in alp and TL areas. Sc and Sa to 1.5. Reports of most recent HST settling into slab. small pockets triggering.

Snowpack Summary

Recent light amounts dry snow has maintained the snow supply for fresh wind slab development and cornice growth. Surface condition in wind-exposed areas is highly variable with scoured areas, sastrugi, and pockets of fresh hard and soft wind slabs. A weak graupel and/or stellar layer down 25-30cm appears to have been the culprit in recent wind slab avalanche activity. Avalanche professionals are gaining confidence in the mid-December persistent weakness, now down 90-170cm, but concern remains for heavy triggers, such as cornice drops, on steep unsupported slopes. When this persistent weaknesses is combined with weak wind slabs, thin trigger points, and other weaknesses within and under the recent storm snow and at the base of shallow snowpack areas, the result is a highly variable snowpack with the potential for step-down deep slab avalanches.

Problems

Wind Slabs

An icon showing Wind Slabs
New snow combined with moderate to strong winds will have created new windslabs behind terrain features and in cross-loaded gullies.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Cornices

An icon showing Cornices
A concern in themselves but also as a heavy trigger for large slab avalanches on the slope below.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Jan 14th, 2012 8:00AM

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