Avalanche Forecast

Issued: Dec 28th, 2016 4:46PM

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

Avalanche Canada rbuhler, Avalanche Canada

Wind slabs are expected to be the main concern for most of the region on Thursday. However, in the deeper snowfall areas of the region, a more widespread storm slab could develop and the local danger could reach HIGH during the peak of the storm.

Summary

Confidence

Low - Intensity of incoming weather systems is uncertain on Thursday

Weather Forecast

The last major low pressure system is expected to bring periods of heavy snowfall to the region on Thursday. 5-10 cm is expected Wednesday overnight and 15-25 cm is expected on Thursday. Alpine wind is forecast to be strong from the southwest on Thursday and freezing levels are expected to reach around 800 m elevation. Mostly dry and sunny conditions are expected for Friday with light alpine wind and freezing levels around 600 m. A weak storm pulse is forecast to bring around 5 cm of snow on Saturday with strong alpine wind from the northwest.

Avalanche Summary

On Wednesday, ski cutting results were limited to two size 1 wind slab avalanches. On Tuesday, explosives and ski cutting produced soft slab avalanches up to size 1.5 which were confined to the new storm snow. On Thursday, wind slabs are expected to be the primary concern in the region. However, if we get higher snowfall amounts than expected, there is a potential for storm slab formation. Where this happens, the local danger rating could be higher.

Snowpack Summary

20-40 cm of new snow has accumulated since Monday. This new snow sits over a variable interface which consists of wind affected surfaces, faceted (sugary) snow, or surface hoar. Recent observations suggest the new snow is well bonded to this interface with exceptions for isolated areas where surface hoar may be preserved. Recently strong southerly winds have formed wind slabs in leeward and cross loaded features in wind exposed terrain. The mid-December interface is now down 90-120 cm and is generally considered to be stable in most areas.

Problems

Wind Slabs

An icon showing Wind Slabs
New snowfall with strong wind is expected to build new wind slabs on Thursday. In deeper snowfall areas of the region, a more widespread storm slab problem could develop.
Use caution in lee areas. Recent wind loading has created wind slabs.Avoid terrain where the surface snow feels stiff or slabby.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Loose Dry

An icon showing Loose Dry
In areas sheltered from the wind, loose sluffing is expected to be a concern in steep terrain features.
Be cautious of sluffing in steep terrain.Use safe ski cutting techniques before entering ski run.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 29th, 2016 2:00PM

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