Avalanche Forecast

Issued: Nov 29th, 2017 3:51PM

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 jlammers, Avalanche Canada

This forecast is based on very few field observations. ThisĀ  high level of uncertainty warrants conservative terrain selection.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Wednesday evening: 5-15cm of new snow / Moderate southwest winds / Freezing level at 1100mThursday: 8-15cm of new snow / Moderate southwest winds / Freezing level at 1100m  Friday: 3-5cm of new snow / Light southerly winds / Freezing level at 1100mSaturday: Mix of sun and cloud / Light southerly winds  / Freezing level at 700m

Avalanche Summary

No new avalanches were reported in this region. This may speak to a lack of observations rather than actual conditions. With forecast wind and snow, a natural storm slab avalanche cycle is expected on Wednesday night and into Thursday.We currently have very limited observations from this region. Please submit your observations to the Mountain Information Network (MIN).

Snowpack Summary

Up to 30cm of new snow has fallen in the past few days. At higher elevations, southerly winds (gusting strong at times) likely redistributed the new snow, forming wind slabs on lee features.Below the recent storm snow you may find a couple of crusts which formed during last week's rain. That said, little is known about the reactivity of these crusts or the elevation bands at which you're likely to find them. A major feature in the snowpack is a crust which formed around November 11th and can be found approximately 100cm down at treeline elevations. We currently have very limited snowpack observations within this region and it is critical to supplement this information with your own observations.The depth of the snowpack varies greatly with elevation. Recent reports suggest the average depth is 200+cm in the alpine, 100-160cm at treeline, and decreasing rapidly below treeline where the primary hazards are rocks, stumps, and open creeks.

Problems

Storm Slabs

An icon showing Storm Slabs
New wind and snow on Wednesday night and Thursday will form reactive new storm slabs. Surface avalanches may "step down" to buried weak layers resulting in surprisingly large avalanches.
Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
Not much is known about the reactivity of a hard crust which lurks deep in the snowpack. This uncertainty warrants conservative terrain selection as an avalanche at this interface could be large and destructive.
Avoid exposure to avalanche terrain during periods of rapid loading by rain, snow, or wind.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Nov 30th, 2017 2:00PM

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