Avalanche Forecast

Issued: Dec 16th, 2019 4:00PM

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

Avalanche Canada MBender, Avalanche Canada

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Snowfall combined with moderate to strong southwest wind Monday night through Tuesday will increase avalanche danger to HIGH.

Summary

Confidence

Moderate - Uncertainty is due to the timing, track, & intensity of the incoming weather system.

Weather Forecast

MONDAY NIGHT: Snow, accumulation 10-15 cm, moderate to strong southwest wind, alpine high temperature -9 C.

TUESDAY: Flurries, accumulation 10-15 cm, moderate to strong southwest wind, alpine high temperature -7 C.

WEDNESDAY: Flurries, accumulation 5-10 cm, moderate south wind, alpine high temperature -6 C.

THURSDAY: Scattered flurries, moderate southwest winds, alpine high temperature -7 C.

Avalanche Summary

There was a report of a skier remotely (from a distance) triggered size 1.5 wind slab avalanche in the alpine on Sunday. No new avalanche activity to report from Friday and Saturday.

Expect to see an increase in natural avalanche activity as storm snow accumulates through Monday night and Tuesday.

Snowpack Summary

25-50 cm of recent snow has accumulated above a widespread layer of large, feathery surface hoar crystals. New snow is expected to continue to accumulate above this layer over the next few days. The increased load is expected to make it more sensitive to human-triggering.

There are a couple of weak layers in the mid snowpack, formed in late November and early December which can be found most notably at treeline, and may present as surface hoar, a crust, facets or a combination, depending on elevation and aspect.

Problems

Storm Slabs

An icon showing Storm Slabs

Snow accumulating above a buried layer of weak surface hoar will create a touchy storm slab problem. The conditions are primed for human triggered avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

A couple of weak layers formed in late November and early December are now sitting about 1 m below the surface.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Dec 17th, 2019 5:00PM

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