Avalanche Forecast

Issued: Nov 25th, 2020 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Deep Persistent Slabs.

Avalanche Canada kdevine, Avalanche Canada

Welcome to the winter 2020/2021 forecast season! Watch for reactive wind slabs at upper elevations, and be aware of the potential for larger avalanches due to a crust that was buried in early November 

Summary

Confidence

Low - Uncertainty is due to the limited number of field observations.

Weather Forecast

WEDNESDAY NIGHT- Cloudy with clear periods and isolated flurries / west wind, 20-40 km/h / alpine low temperature near -9

THURSDAY- Cloudy with sunny periods and isolated flurries / west wind, 20-40 km/h / alpine high temperature near -7 / Freezing level 1000 m

FRIDAY- Cloudy with sunny periods and isolated flurries / southwest wind, 30-50 km/h / alpine high temperature near -5 / Freezing level 1000 m

SATURDAY- Mainly cloudy with scattered flurries / southwest wind, 15-20 km/h / alpine high temperature near -5 / Freezing level 1000 m 

Avalanche Summary

There have been very few reports of avalanches in the region, however observations are limited at this time. 

In the past week there have been a few size 2 avalanches reported on the early November crust. These have been triggered by both humans and explosives.

If you get out into the mountains, please consider sharing your observations on the Mountain Information Network!

Snowpack Summary

The Purcells have seen up to 30 cm of fresh snow this week. There is a crust from early November that is down approximately 50-75 cm. This layer has been observed to have weak, sugary facets above and below it. Recent observations of this layer indicate that it has the potential to be triggered by humans.

Terrain and Travel

  • Be careful as you transition into wind affected terrain.
  • In times of uncertainty conservative terrain choices are our best defense.

Problems

Wind Slabs

An icon showing Wind Slabs

Recent fresh snow and wind has formed wind slabs in lee terrain features at upper elevations.

Aspects: North, North East, East, South East, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

A crust from early November exists down about 50-75 cm. This layer has weak, sugary facets above and below it. Recent observations suggest that it has the potential to be triggered by humans.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Nov 26th, 2020 4:00PM