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Archived

Avalanche Forecast

Dec 31st, 2011–Jan 1st, 2012
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable

Regions: Northwest Coastal.

Confidence

Fair - Freezing levels are uncertainfor the entire period

Weather Forecast

Heavy precipitation and strong southerly winds are forecast for late sunday and into monday morning. Continued moderate precipitation will follow throughout monday and tuesday with moderate to strong southwest winds.Freezing levels are uncertain for the forecast period; some models showing freezing levels at 650m while other show freezing levels shooting to 1500m. Stay tuned for more info.

Avalanche Summary

Wind slabs and cornice releases dominated recent avalanche observations. Size 2 natural slab activity triggered by cornice fall and numerous skier-triggered size 1 slabs reported in the northern part of the region.Numerous natural size 2 slabs reported in the Skeena area.

Snowpack Summary

A relentless pummelling by snow, strong to extreme winds, and fluctuating freezing levels over the past week has added around 130cm of new snow near Terrace and around 75cm near Stewart. Strong south to southwest winds have created hard and soft wind slabs on lee slopes. Large sensitive cornices also exist.Deeper in the snowpack, buried surface hoar and a crust-facet combo (which extends up to alpine elevations in the south and to 1000m in the north) remain a cause for concern, with the potential for deep, destructive avalanches. Recent observations suggest these layers may be gaining strength; however, I wouldn't write them off just yet.

Avalanche Problems

Wind Slabs

Deep wind slabs will continue to develop in exposed lee and cross-loaded terrain in the alpine and at treeline. Large, sensitive cornices are also a current concern above lee slopes.

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

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1 - 5

Storm Slabs

Storm slabs could be triggered by the weight of a person or a snowmobile.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 5

Persistent Slabs

There is a possibility of highly destructive avalanches where the deeply buried mid-December crust/facet layer persists. The probability of a deep release may be lower; however, the consequences would be very high.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 6