Avalanche Forecast

Issued: Dec 1st, 2011 8:57AM

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

pmarshall, Avalanche Canada

Northwest Coastal.

Danger ratings remain elevated due to continued snowfall and very strong winds on Thursday.

Summary

Confidence

Poor - Due to limited field observations

Weather Forecast

Conditions will gradually start to dry out on Friday as a ridge of high pressure builds over the province. Winds should ease to moderate from the NW on Friday morning and remain in the light to moderate range throughout the weekend. A mix of sun and cloud is expected on Saturday. Sunday should be mainly cloudy with a chance of flurries. The freezing level should hover around 600-800m throughout the forecast period.

Avalanche Summary

Recent avalanche control work along the northern highway corridors have produced results up to Size 3, mainly involving the recent storm snow. I suspect a natural avalanche cycle is likely late Thursday and into Friday in response to the forecast cranking winds and 15-30cm of snow.

Snowpack Summary

Very strong SW-NW winds may wreak havoc on the snowpack creating scoured areas and soft or hard wind slabs in exposed lee terrain and cross-loaded gullies or terrain features. Coastal areas are reporting a very deep and strong snowpack - at or near record levels for this time of year. A buried surface hoar layer may be found down 100-150cm near Terrace, but there is no recent information on the presence and sensitivity of this layer.

Problems

Wind Slabs

Hard and soft wind slabs are likely in exposed terrain on a variety of aspects well into treeline.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Storm Slabs

Storm snow instabilities may be triggered by a skier or snowmobile, or by additional loading from snow or wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 5

Valid until: Dec 2nd, 2011 8:00AM