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Avalanche Forecast

Dec 28th, 2013–Dec 29th, 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
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

Regions: South Columbia.

Confidence

Fair - Intensity of incoming weather systems is uncertain on Monday

Weather Forecast

Sunday: Another series of weather systems starts to affect the interior. Light snowfall, alpine temperatures -6, winds light to moderate from the northwest.Monday: Light to moderate snowfall, Alpine temperatures -5, freezing level at 1200m, winds light west.Tuesday: Mainly cloudy with isolated flurries. Alpine temperatures -5 and freezing level at 1200m.

Avalanche Summary

A few slab and loose avalanches to size 1.5 have been reported in the last 2 days. These are isolated to the most recent storm snow.

Snowpack Summary

Recent Moderate to strong west and southwesterly winds have built new wind slabs in alpine and treeline lees. 30-50 cm of storm snow sits on a weak layer consisting of surface hoar crystals, stellar crystals and/or crust. Around 60-90 cm below the snow surface, the early December surface hoar, facetted snow, and/or a crust interface sits and has been reportedly more stubborn to rider triggers. The late-November persistent weak layer consists of a sun crust on steep south facing slopes and surface hoar in sheltered areas. It is now buried 80-110cm below the surface. Snowpack tests vary on this interface with some results producing "sudden" shears and others producing no results. This interface is generally considered to be dormant. However, professional operators are keeping a close eye on it.A weak layer of facets sitting on a crust that formed in October, sits near the base of the snowpack. This layer is predominantly found on north-facing alpine slopes with smooth ground cover. Triggering this weakness is unlikely, however if triggered the resulting avalanche would potentially be a large event with high consequences.

Avalanche Problems

Wind Slabs

Recent westerly winds have created windslabs in the lee of terrain features.
Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Persistent Slabs

Several persistent weaknesses exist in the mid-snowpack.
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Carefully evaluate and use caution around thin snowpack areas.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely - Possible

Expected Size: 3 - 5