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Avalanche Forecast

Dec 11th, 2013–Dec 12th, 2013
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
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
2: Moderate
The avalanche danger rating at treeline will be moderate
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: Sea To Sky.

Avalanche danger will increase throughout the day.If snowfall amounts or wind strength are greater than forecast then  avalanche danger may be higher than posted.

Confidence

Fair - Intensity of incoming weather systems is uncertain on Thursday

Weather Forecast

An intense low pressure system continues to churn in the Gulf of Alaska. The latest weather models are showing that the coast is going to receive significantly more precipitation than previously forecast.Thursday: The first in a series of systems will hit the region . Expect up to 30cm of snow at higher elevations. Moderate southwesterly winds at ridgetop will build to strong later in the day. Freezing levels with rise to 1000m.Friday: A brief clearing with light precipitation, strong southwest winds at ridgetop. Freezing levels dropping to 700m.Saturday: Likely moderate to heavy snow as the next system hits the region, with moderate winds from the west.

Avalanche Summary

No recent avalanche have been reported.

Snowpack Summary

Snowpack depths vary greatly across the region with an average of 100cm at treeline. Terrain below treeline is still mostly below threshold for avalanche activity.Cold temperatures have driven faceting throughout the pack, especially in shallow areas. Arctic outflow winds have scoured N and NE slopes leaving a thin layer of facets sitting on a crust. In protected locations surface hoar has been growing over the last couple of days at all elevations. These two week surface layers will cause a problem given a significant load of storm snow Further down a few crusts can be found near the ground, especially at higher higher elevations.

Avalanche Problems

Wind Slabs

A layer of surface facets above a crust exists on previously wind scoured N-NE aspects. As southwest winds load these features through the day avalanche danger will increase.
Avoid freshly wind loaded features.>Avoid regrouping in runout zones.>Ski short pitches and regroup in safe spots.>Choose regroup spots that are out of avalanche terrain.>

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

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 2 - 4

Storm Slabs

Up to 30 cm of new snow will form wide spread slabs. Storm snow avalanche are often triggered from convexities so be wary of steep unsupported terrain. A thin early season snow pack could increase the consequences of terrain traps.
Choose well supported terrain without convexities.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious. This is especially true on glaciers where storm snow may hide open crevasses.>Avoid steep, open glades in the forest.>The snowpack on glaciers is shallow, and the use of a rope is recommended.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3