Avalanche Forecast

Issued: Dec 23rd, 2011 8:58AM

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

mpeter, Avalanche Canada

South Columbia.

Stay aware of changing conditions. Danger may be locally higher due to more intense precipitation or wind.

Summary

Confidence

Fair - Due to variable snopack conditions

Weather Forecast

Saturday: Mostly cloudy with flurries. Expect moderate southwest winds and temperatures reaching -4. Due to the nature of the weather pattern, expect more precipitation on the western half of the region and on west facing slopes. Sunday: A weak cold front passes through the region giving unsettled skies with a chance of flurries. Continued southwest winds and freezing levels reaching 1100m. Monday: Expect clearing conditions under southwest winds and freezing levels to 1100m.

Avalanche Summary

Recent explosive control yielded one 2.0 slab, and we have a report of a small accidental skier triggered slide with no involvement. Both of these events were in the northern part of the region. As the load increases through the weekend, the likelihood of triggering will go up. Threshold for human triggering will precede natural releases.

Snowpack Summary

Northern and western areas have seen up to 50 cm of recent storm snow, while areas further south have seen only 20cm. Consistent westerly winds have lee loaded alpine and open treeline terrain, creating a windslab problem. In many areas, the new snow sits above a well developed surface hoar layer from mid December. Stability test still show sudden results on this layer in the moderate to hard range, and whole block rutchblocks have also been reported. Where this layer is present, it should be treated with respect. Lower in the snowpack, the mid-layers are well-consolidated and strong.

Problems

Wind Slabs

Shifting winds have set up this problem on a variety of aspects, particularly north through south east.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

Right now this is more of a concern in the northwest corner of the region. As more snow falls, this problem will increase across the rest of the region. Most pronounced on sheltered, shady aspects (i.e. large, open glades facing north and east).

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 4

Valid until: Dec 24th, 2011 8:00AM