Avalanche Forecast

Issued: Dec 8th, 2019 4:00PM

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

Avalanche Canada MBender, Avalanche Canada

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There is uncertainty with the reactivity of several buried weak layers. Best to adopt a conservative approach while the snowpack adjusts to the increased load from recent snowfalls.

Summary

Confidence

Moderate - Uncertainty is due to the complexity of the snowpack’s structure.

Weather Forecast

Sunday: Mainly clear with cloudy periods, alpine temperature -9, moderate northwest wind.

Monday: Mix of sun and clouds, alpine temperature -7, moderate north wind.

Tuesday: Mix of sun and cloud, alpine temperature -8, light northwest wind.

Wednesday: Cloudy with flurries, alpine temperature -8, light southwest wind.

Avalanche Summary

Reports from Friday and Saturday indicate skier triggered and natural storm slab avalanches size 1-2 on all aspects. There were also a few reports of persistent slab avalanches failing on a layer of surface hoar down 80-120 cm at treeline elevations over the past several days. At least one of these was remotely triggered (from a distance). Additionally there reports of explosive triggered avalanches to size 3 in the trans Canada highway corridor on Friday.

Snowpack Summary

30-60 cm of new snow from late last week has covered a layer of feathery surface hoar that has been found at all elevations. A thick layer of faceted crystals, previously wind-affected surfaces, and/or surface hoar in sheltered areas (around treeline and below) is now 50-90 cm below the surface.

An additional layer of surface hoar may be found in sheltered areas around treeline down 70-120 cm. In some areas this may sitting on a thin crust.

A variety of crusts from late October are buried deeper in the snowpack.

Problems

Storm Slabs

An icon showing Storm Slabs

30-60 cm of new snow accumulating late last week has formed a reactive storm slab. In some areas this may be sitting on a layer of weak surface hoar

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

There is a lot of uncertainty associated with the reactivity and distribution of a surface hoar/crust layer buried 80-120 cm. This layer is most likely found in sheltered openings around treeline and below.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Dec 9th, 2019 5:00PM