Avalanche Forecast

Issued: Jan 14th, 2012 9:17AM

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

mbender, Avalanche Canada

South Columbia.

The following ratings are based on snowfall amounts for the northeastern portion of the region (20-35cm of new snow).

Summary

Confidence

Fair - Due to variable weather conditions on Sunday

Weather Forecast

SUNDAY: Light precipitation with light winds from the west. Temperatures dropping to -15 degrees celsius. MONDAY: Light precipitation with continued cold temperatures. Winds moderate from the west. TUESDAY: Continued light precipitation and cold temperatures.

Avalanche Summary

Recent reports indicate 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. Other reports indicate natural avalanches running to size 2 on northerly aspects in the alpine.

Snowpack Summary

15-30cm of dry 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).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 100-180cm, 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 snow and wind have created new windslabs and buried recently formed ones.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

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 - 4

Loose Dry

Up to 35 cm of very light new snow sluffing easily in steep unsupported terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Jan 15th, 2012 8:00AM