Avalanche Forecast

Issued: Dec 19th, 2011 9:21AM

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

ccampbell, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Good - -1

Weather Forecast

Tuesday: Light snowfall with a couple of centimetres accumulation, freezing levels dropping throughout the day to valley bottoms, and strong westerly mountaintop winds. Wednesday: Mostly clear and dry, freezing levels in valley bottoms, and moderate northerly winds. Thursday: Winds are expected to shift to westerlies as cloud cover increases.

Avalanche Summary

Recent reports include several human triggered relatively harmless thin soft wind slab avalanches running fast and loose on large surface hoar.

Snowpack Summary

10-15 cm low density snow sits above a weak layer of large surface hoar and/or facets, with and associated crust on sun-exposed slopes. At present, the snow above this weak layer is not sufficiently deep or cohesive for large slab avalanches. We typically see dangerous slab avalanches start to occur when the depth to the weak layer reaches approximately 40cm. Below these potential near surface issues, the mid pack is strong. The basal snowpack layers are faceted, however, we have not received any recent reports of associated instabilities.

Problems

Wind Slabs

Fresh wind slabs are lurking below ridge crests, behind terrain features, and in cross-loaded gullies.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 20th, 2011 8:00AM