Avalanche Forecast

Issued: Jan 21st, 2012 10:32AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs and Wind Slabs.

Avalanche Canada jlammers, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertain on Tuesday

Weather Forecast

Sunday: 10-12cm of snow / Moderate westerly winds / Freezing level at surfaceMonday: Light snowfall / Moderate southwest winds / Freezing level at 500mTuesday: Moderate snowfall / Strong southwest winds / Freezing level at 700m

Avalanche Summary

Expect widespread avalanche activity in the wake of saturday's storm.

Snowpack Summary

On friday and saturday storm snow accumulations amounted to over 30cm in some parts of the region. The upper snowpack is now characterized by new wind slabs and storm slabs sitting on top of dry loose snow. Due to the nature of the most recent storm (warmer temperatures, moderate winds) you can expect a more reactive "upside-down" snowpack in wind-exposed areas where a denser layer over-rides colder, softer snow where weaknesses are more likely to endure.Various surfaces buried in early January including a rain crust, spotty surface hoar and preserved stellar snow crystals are now about 80-100cm deep and may provide a sliding layer for storm-related avalanches over the weekend. A surface hoar layer buried in mid-December is gaining strength, but professionals are still treating it with caution, as the consequences of an avalanche on this layer would be high. Occasional hard, planar results have been reported on this layer in snowpack tests. It's now down about 140cm in the snowpack.

Problems

Storm Slabs

An icon showing Storm Slabs
A classic recipe for storm slabs has evolved: moderate to heavy snowfall with rising temperatures landing on loose dry snow. Watch for storm snow avalanches, especially in steep or convex terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 6

Wind Slabs

An icon showing Wind Slabs
Moderate ridgetop winds will have shifted snow into wind slabs on leeward slopes.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 5

Valid until: Jan 22nd, 2012 8:00AM