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Avalanche Forecast

Dec 25th, 2011–Dec 26th, 2011
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
3: Considerable
The avalanche danger rating below treeline will be considerable

Regions: South Coast.

Check out the latest post in the Forecaster's Blog for advice on how to stay safe in the backcountry over the holidays.

Confidence

Poor - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

A series of frontal systems will affect the region over the next several days bringing periods of moderate to heavy precipitation followed by brief dry spells. Monday: 10-25cm of snow (greater amounts further south). Moderate to strong S-SW winds. Freezing level (FL) around 800m. Tuesday: 5-10cm. Moderate W-SW winds. FL 1000m rising to 1800m in the evening. Wednesday: 10-20cm. Moderate W-SW winds. FL around 1800m.

Avalanche Summary

No new avalanche activity reported in the last 24 hours. Fresh wind slabs and cornices are sensitive to human-triggers and will continue to be with forecast weather. There was one report of a Size 2 intentionally triggered avalanche in the Duffy Lake area on Thursday. This occurred in the alpine just below the ridge crest on a wind loaded NE aspect.

Snowpack Summary

Dribs and drabs of new snow with moderate winds have been the norm over the last week. Wind-exposed slopes are predominately scoured and pressed, with pockets of wind slab from 10 to 35cm deep on North to East aspects at treeline and in the alpine.This recent snow overlies a weak rain crust that formed last weekend. This crust extends to treeline elevations and overlies buried surface hoar and/or facets 10cm below. Generally speaking, confidence in this interface is growing, especially since it has'nt seen a significant load at the elevations where it exists. In the alpine where the crust does not exist, a stiffer wind slab may over-ride surface facets that formed during the early December dry spell. The mid and lower snowpack are generally well-settled and strong. Snowpack depths at treeline sit at about 130 throughout the region.

Avalanche Problems

Wind Slabs

Wind slabs have developed in exposed lee and cross-loaded terrain and may be quite reactive, especially where they over-ride last weekends rain crust or weak facets (sugar snow) from the early December dry spell.

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

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1 - 4

Storm Slabs

Weaknesses may exist within or under the new storm snow. A greater concern where daily snowfall amounts exceed 20cm.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 3