Avalanche Forecast

Issued: Jan 15th, 2012 9:06AM

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

mbender, Avalanche Canada

South Columbia.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

MONDAY: Light precipitation in the afternoon combined with colder temperatures and light west winds. TUESDAY: Cold temperatures with light flurries. Winds light to moderate from the west. WEDNESDAY: Cold and clear.

Avalanche Summary

Recent reports indicate loose snow avalanches triggering very easily in steep unsupported terrain on all aspects. Some these avalanches were stepping triggering some of the weaknesses deeper in the snowpack to size 2. On Friday a rider triggered size 2.5 cornice failure on a northeast aspect stepping down to ground in a thin snowpack area. This cornice pulled back to the ridge line.

Snowpack Summary

20-40 cm of low density new snow combined with wind has encouraged additional slab development and cornice growth. This new snow now sits on a variety of surfaces (facets, surface hoar in sheltered areas, wind crust, soft slabs and hard slabs).Avalanche professionals are gaining confidence in the mid-December persistent weakness, now down 110-190cm, 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 a variety of other buried weaknesses the result is a highly variable snowpack with the potential for step-down deep slab avalanches.

Problems

Wind Slabs

New windslabs developing below ridgecrests.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Loose Dry

Up to 40 cm of very light new snow sluffing easily in steep, unsupported terrain

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

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 16th, 2012 8:00AM