Avalanche Forecast

Issued: Nov 15th, 2021 4:00PM

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

Chris Gooliaff,

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An unprecedented dump (150+cm in 48hrs) for mid-Nov has dramatically changed the landscape. Storm slabs are prevalent at all elevations and aspects.

Travel cautiously for the next couple of days, observing how this huge load settles on the slopes.

Summary

Weather Forecast

An Arctic ridge will move into the region early Tues am, bringing cold temps and stable weather.

Tonight: Flurries, 6cm, Alpine high -13*C, mod/strong W winds

Tues: Cloudy w/ sun and isolated flurries, Alpine high -13*C, light/mod W winds

Wed: Cloudy w/ sunny periods, Alpine high -8*C, light SW winds

Thurs: Cloudy, Alpine high -8*C, light SW winds

Snowpack Summary

150+mm of precip in the past 48 hours has formed a remarkable storm slab! The new snow has fallen with moderate SW winds and mild temps. Snow depths have ballooned, with 1m at Rogers Pass, over 1.5m at tree-line, and 2+m in the Alpine. There are 2 crusts to date, the Nov 5th buried ~100cm and the Oct crust that lies near the base of the snowpack.

Avalanche Summary

Numerous large avalanches (sz 3-3.5) observed along the highway corridor, with many running down into valley bottoms.

Expect this natural avalanche cycle to slow on Tues with the end of the snowfall and cooling temps.

Confidence

Due to the number and quality of field observations

Problems

Storm Slabs

An icon showing Storm Slabs

In the past 48hrs, we received 100cm of snow at 1300m and 150+cm in the alpine. Warm temps and strong SW winds have helped form this load into a cohesive storm slab. This sits on a widespread rain crust that has been found high into the Alpine.

  • Use caution in alpine and open treeline lees. Recent snowfall has created storm slabs.
  • Avoid paths that have not avalanched recently.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Loose Dry

An icon showing Loose Dry

In the Alpine and upper Tree-line, expect fast-moving, loose, dry avalanches in steep, sheltered/confined terrain features.

  • Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Nov 16th, 2021 4:00PM