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Avalanche Forecast

Feb 20th, 2013–Feb 21st, 2013
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
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
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: Northwest Coastal.

Confidence

Good

Weather Forecast

Synopsis: A series of frontal systems is expected to affect the region over the next few days bringing steady precipitation and seasonal temperatures.  Overnight and Thursday: Periods of snow – 20-30 cm. The freezing level is around 600 m. Winds are moderate to strong from the west-southwest. Friday: Heavy snowfall – 30-40 cm. The freezing level remains around 500-600 m and winds are strong from the west.Saturday: Cloudy with light snow. The freezing level is around 500 m and winds ease to moderate from the southwest.

Avalanche Summary

Recent natural avalanche activity is limited to size 1-1.5 loose snow avalanches in steep terrain. Explosive control in Bear Pass produced a few size 2-2.5 slab avalanches on Tuesday.

Snowpack Summary

A layer of surface hoar and a sun crust are now buried by a few cm's of new snow. Below this the recent storm snow has settled and gained strength over the past couple days. Pockets of wind slab have formed on a variety of aspects in exposed terrain near ridge crests, and may be susceptible to triggering in steep terrain. Cornices that now loom over many features may become weak with continued growth and/or daytime warming. The mid and lower snowpack layers are generally well settled.

Avalanche Problems

Storm Slabs

New snow may not bond well to the previous snow surface (surface hoar, wind slab, sun crust) and may be easily triggered by the weight of a rider. Be especially wary of exposed north through east facing slopes where wind loading is likely.
Avoid freshly wind loaded features.>Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 2 - 5

Cornices

The recent snow and wind have been building cornices on lee features. These cornices are likely weak and may fail at anytime. Cornice failure has the potential to trigger large avalanches.
Give cornices a wide berth when travelling on or below ridges.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4