Avalanche Forecast

Issued: Dec 22nd, 2012 9:33AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Loose Dry.

swerner, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

A Southern flow with embedded troughs will continue to dominate the region through Monday, bringing additional snowfall amounts. A weak ridge develops Monday showing dryer conditions throughout the day.Saturday night into Sunday: Snow amounts 5-10 cm overnight with an additional 5-10 cm tomorrow, ridgetop winds light from the SW, alpine temperatures near -6. Monday: Light snowfall amounts in the morning, ridgetop winds light from the SE, and alpine temperatures near -4.Christmas Day: Mainly dry with possible sunny breaks, ridgetop winds light from the South, and alpine temperatures -10.

Avalanche Summary

Explosive testing on Friday showed numerous size 1.0-2.0 slab avalanches on N-NW aspects 2000 m and above. Several natural size 1.0 loose snow avalanches occurred from steeper terrain features.

Snowpack Summary

Around 110 cm new snow has fallen in the last week. Consistent, moderate SW winds have been retributing the new snow onto lee slopes and behind terrain features. In areas of wind effect, expect the storm slab to be stiffer, easy to trigger and more reactive. In most places the slab is still relatively unconsolidated and soft and it is not propagating far. Expect heavy sluffing in steep terrain. Large sluffs may be able to push you around; beware of terrain traps. Below the storm snow sits a well settled mid-pack that has not been showing shears in snow profile tests.

Problems

Storm Slabs

Additional snow and wind will continue to build touchy storm slabs at all elevations. Recent light snow may also be transported by forecast strong southwest winds into deep wind slabs on North through East aspects.

Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>Be cautious as you transition into wind affected terrain.>The new snow will require several days to settle and stabilize.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Loose Dry

Loose dry snow remains unconsolidated in terrain that is protected from the wind. There is a lot of new snow; sluffing may entrain enough snow to bury a skier/rider.

On steep slopes, pull over periodically or cut into a new line to manage sluffing.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Valid until: Dec 23rd, 2012 2:00PM