Avalanche Forecast

Issued: Nov 16th, 2021 4:00PM

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

Chris Gooliaff,

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Cold temps have locked the huge load of storm snow in place. That being said, I've never seen 200cm of snow fall in 3 days, so I would stay conservative in my run choices.

Let the storm snow settle a little longer. Winter is just beginning...

Summary

Weather Forecast

Continuing cool temps with isolated flurries

Tonight: flurries, 6cm, Alpine low -15*C, mod/strong W winds

Wed: mix of sun and cloud, Alpine high -8*C, light SW winds

Thurs: cloudy with isolated flurries, Alpine high -8*C, light SW winds

Fri: cloudy with isolated flurries, Alpine high -10*C, light W winds

Snowpack Summary

204mm of precip in the past 72 hours at Tree-line! The storm snow arrived cold, then warmed considerably mid-storm, and cooled at the tail-end of the event. There will be rain crusts and moist snow layered in the new snowfall. This massive load sits upon the widespread Nov 5 rain crust, which was found below Tree-line to 2400m in the Alpine.

Avalanche Summary

A large natural avalanche cycle ripped through Rogers Pass Sunday and Monday, with numerous large avalanches (sz 3-3.5) observed throughout the highway corridor. Many avalanches had enough energy to overcome the rough slide-alder slopes and make it to valley bottom.

Natural avalanche size and frequency has decreased with the cooler temps.

Confidence

Due to the number of field observations

Problems

Storm Slabs

An icon showing Storm Slabs

In the past 72hrs, we received 200+mm 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.

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

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: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Nov 17th, 2021 4:00PM