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Avalanche Forecast

Dec 10th, 2013–Dec 11th, 2013
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
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
1: Low
The avalanche danger rating below treeline will be low

Regions: South Coast.

Confidence

Fair - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

The arctic air mass that has be sitting over much of BC for the last week is starting to retreat as a series of storm fronts drive warmer air into the province. Expect isolated flurries light winds from the southwest on Wednesday. The precipitation will intensify slightly on Thursday with southwest winds at ridgetop strengthening through the day. Friday will see a brief clearing with sunny periods and light winds.

Avalanche Summary

A large avalanche was recently reported as having failed on or close to the ground in the southern Cascades. This may be an isolated incident but could be indicative of a more widespread weakness at the base of the snowpack in the Alpine.

Snowpack Summary

Snowpack depths vary greatly across the region with 160cm at treeline in the Cascades but 50 cm along the Duffy. Terrain below treeline is still mostly below threshold for avalanche activity.Arctic outflow winds have redistributed the snows that fell last week forming wind slabs on S to SW slopes at treeline and in the alpine. Surface hoar has been growing over the last week in protected locations near tree line while the cold temperatures have driven faceting throughout the snowpack.A few crusts can be found near the ground, especially at higher higher elevations. Cold temperatures may have weakened the snow around these crusts - especially in alpine areas with a thinner snowpack.

Avalanche Problems

Wind Slabs

Northeast winds redistributed the snow from last week forming wind slabs in lee features at ridgeline and on cross-loaded slopes. Don't let wind slabs in unusual places catch you by surprise.
Be cautious as you transition into wind affected terrain.>Avoid lee and cross-loaded terrain near ridge crests.>Avoid travelling in areas that have been reverse loaded by winds.>

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 3

Deep Persistent Slabs

A crust from early in the season may be a problem in isolated thin and rocky areas near the bottom of the snowpack at higher elevations.
Carefully evaluate and use caution around thin snowpack areas.>Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 2 - 5