Avalanche Forecast

Issued: Dec 15th, 2014 8:19AM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Wind Slabs and Persistent Slabs.

ccampbell, Avalanche Canada

South Rockies.

Danger ratings trending down due to low freezing levels after the recent rain.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Mainly sunny and dry for the forecast period. Freezing levels will remain in valley bottoms with alpine temperatures reaching -5C and light to moderate westerly alpine winds.

Avalanche Summary

No new reports of avalanches from the region on Sunday or Monday morning.

Snowpack Summary

Surface hoar is likely growing on a thick hard supportive near-surface rain crust that extends as high as 2100 m, with as much as 15cm of fresh snow on it. Last week's rain and subsequent freezing temperatures has effectively stabilized the snowpack at all but the highest elevations. However, in high alpine areas that did not get rain during the recent storm, there may be a buried persistent weak layer of crust and/or facets that is now down between 70-100 cm. This buried crust from November may continue to be triggered by large additional loads. Pockets of fresh wind slab may also be triggered at or near ridgetops in areas where the snow was dry enough to be transported by the strong Southwest winds during the storm.

Problems

Wind Slabs

Wind slabs may continue to be triggered from human activity at high alpine elevations. Expect wind slabs to gradually increase their bond to the old surface.

Be cautious as you transition into wind affected terrain.>Avoid lee and cross-loaded terrain near ridge crests.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

High alpine terrain that did not get rain during the last storm may continue to have a storm slab above a deeply buried crust that could act as a smooth sliding layer.

Avoid large alpine slopes that have a deeply buried crust with facets. >Avoid slopes with variable snowpack depths. Avalanches may be triggered from thin spots around boulders or small trees.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

2 - 4

Valid until: Dec 16th, 2014 2:00PM