Avalanche Forecast

Issued: Dec 9th, 2011 9:09AM

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

mpeter, Avalanche Canada

South Columbia.

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

Saturday: Expect high clouds with winds reaching 40-70 km/h from the southwest and temperatures climbing to -5. Sunday & Monday: The ridge rebuilds giving mostly clear skies and moderate westerly winds. Freezing levels could peak at 1200m on Monday.

Avalanche Summary

A couple of large (size 2.0-2.5) natural avalanches have been reported releasing along the TCH highway corridor.

Snowpack Summary

The Surface Hoar continues to grow due to the clear and cold nights and the cold temperatures are also promoting near surface facetting. Expect to find a sun-crust that has formed in the alpine on south through west aspects. Wind slabs persist in the alpine and in large openings at treeline. Some areas have a rain-crust below treeline from the 28th of November that has been buried by about 20 cms of snow. This rain-crust may be developing facets, and could become a layer of interest after it is buried by more of a load. There is still some concern associated with the November 7 surface hoar layer. This layer is buried 100-150 cms. Tests are showing that this layer is getting harder to trigger, but if an avalanche does release on this layer, it is likely to be large and destructive.

Problems

Wind Slabs

Hard windslabs continue to be an issue in the alpine and in large openings at treeline.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Hard to trigger in most areas, but the consequences of triggering a slide on this layer may be a very large avalanche. Weaker thin spots around protruding rocks or clumps of small trees may be likely trigger locations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 10th, 2011 8:00AM