Avalanche Forecast

Issued: Dec 12th, 2012 9:15AM

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

slemieux, Avalanche Canada

South Columbia.

Summary

Confidence

Fair

Weather Forecast

A weak system will cross the region in the evening Thursday and bring very light precipitations and light North West winds becoming moderate from the South West later. Temperatures will stay cool for the entire period . Mostly cloudy with chances of flurries for Friday with light winds from the North West. Later Saturday, another upper trough is expected to spread moderate snow accumulations over the region with moderate winds from the South.

Avalanche Summary

Some small soft slabs and loose dry avalanches were skier triggered yesterday in steep convex terrain.

Snowpack Summary

20 cm of new snow fell from the recent storm with moderate winds creating touchy soft slabs at treeline and most likely thinker and harder windslabs in the alpine on Easterly aspects. Indeed, snowpack test showed easy result within the storm snow. This new load is sitting on the Late November surface hoar layer now down around 100 cm and the early November crust down 200cm. Because of the stability tests variations (from no results to suddan planars), the limited quantity of observations and significant depth of those layers, they remain the primary concerns.

Problems

Deep Persistent Slabs

The early November rain crust is deeply buried. Releases on this layer will be very large and destructive.

Common trigger points for this kind of layer is thin rocky areas and areas with smooth ground cover. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

4 - 7

Persistent Slabs

The weak layer is buried down about 100 cms and recently has been loaded by new snow and wind. Wind slabs above may trigger this deeper layer in unsupported terrain. Elevations between 1600-2100 metres are the most suspect.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 6

Wind Slabs

Use ridges or ribs to avoid pockets of wind loaded snow.>Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Dec 13th, 2012 2:00PM