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Archived

Avalanche Forecast

Jan 27th, 2012–Jan 28th, 2012
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: South Coast.

Confidence

Fair - Intensity of incoming weather is uncertain on Sunday

Weather Forecast

Saturday: very light snowfall increasing in the evening / moderate southwest winds with strong gusts / freezing level rising to 900m Sunday: light to moderate snowfall / strong southwest winds / freezing level rising to 1100m Monday: very light snowfall / light southwesterly winds / freezing level at 800m

Avalanche Summary

On Friday explosives testing in the Duffey Lake area produced avalanches to size 3. In the Coquihalla area, explosives control produced numerous size 2-3 avalanches with crowns ranging from 30-150cm.

Snowpack Summary

Friday saw little in the way of new snow for the South Coast Inland region, but in the big story in the region is moderate to heavy snowfall and fluctuating freezing levels over the past week accompanied by generally high winds. It seems that as soon as one storm interface starts to strengthen, another system comes in and creates new destructive wind and storm slabs. Adding to the complexity of the storm slab problem is the January 20th interface where facetted snow from the mid-January cold snap acts as a bed surface for all of this past week's snow. The probability of any activity at this interface is decreasing the consequences of a slide would be large and very destructive.With the recent wind and snowfall there are widespread unstable cornices. Any cornice fall would be destructive by itself, but could also be a trigger for the slope below. Persistent weak layers lower down in the snowpack have generally ceased to be of concern, except perhaps in very isolated, thin rocky areas. Most recently, the Coquihalla area has been receiving the most snowfall with current snowpack depths at treeline amounting to 390cm. In the Duffey Lake area, treeline depths are closer to 240cm.

Avalanche Problems

Wind Slabs

Continued strong SW winds have set up deep wind slabs on lee and cross-loaded slopes.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 5

Storm Slabs

Numerous deep storm interfaces exist in the upper snowpack. Watch for triggering on steep or unsupported terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 6

Cornices

High winds, moderate temperatures and recent snow will have added to a cornice problem. Cornice fall will be easy to initiate and can become a trigger for the slope below.

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

Elevations: Alpine.

Likelihood: Likely

Expected Size: 1 - 6