Avalanche Forecast

Issued: Dec 19th, 2012 10:09AM

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

Avalanche Canada ghelgeson, Avalanche Canada

Summary

Confidence

Good

Weather Forecast

Wednesday night:  Strong to Extreme SW winds at ridgetop.Thursday: Strong to Extreme SW winds at ridgetop. 1500m temp -5. Moderate to heavy snow totaling 5 - 15cm with greatest accumulations in the south. Friday: Moderate to Strong southerly winds. 1500m temp -5.  Occasional flurries.Saturday:  Light West Winds.  Treeline temp -1. Light snow.

Avalanche Summary

There was a widespread cycle of small natural and skier triggered soft slab and loose snow avalanches on Monday. Soft new cornices were also falling off and triggering soft slabs up to size 2. Some larger (size 2-3) naturally triggered slabs were observed to the north of the region. Explosives triggered a size 2 soft slab which stepped down to the late November surface hoar layer in a steep rocky area in the Selkirks on Sunday.

Snowpack Summary

More than 120 cm of snow has accumulated this week in some areas. Various storm snow instabilities have been observed. In areas affected by recent SW to SE winds, new wind slabs and touchy cornices exist at alpine and treeline elevations. In areas sheltered from the wind, the new snow is sluffing fast and far, with enough ?push? to get you into trouble. The mid-pack is reported to be settling well. The late November surface hoar, down 100-160 cm (between 1500 and 2000 m), is producing moderate to no results in snowpack tests, with isolated sudden results. The early November crust, near the base of the snowpack, has produced occasional sudden results in snowpack tests. Professionals are still cautious about these lingering persistent slab problems, but the likelihood of triggering is low. Be wary of steep complex terrain with a shallow snowpack, where triggering a persistent weakness is more likely.

Problems

Wind Slabs

An icon showing Wind Slabs
Increasing winds and new snow continue to build fresh sensitive wind slabs which could be triggered by the weight of a person or snowmobile. A wind slab or storm slab could trigger a deeper weak layer.
Conditions are changing and you need to adapt your plans accordingly. Avoid wind exposed terrain at and above treeline.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 6

Loose Dry

An icon showing Loose Dry
Deep dry snow failing as a loose dry avalanche can trip you up or push you into a terrain trap. Take care in any steep terrain.
Be aware of party members below you that may be exposed to your sluffs.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Dec 20th, 2012 2:00PM

Login