Avalanche Forecast

Issued: Nov 27th, 2020 4:00PM

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

Avalanche Canada JSmith, Avalanche Canada

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Recent snow and strong southwest winds have formed widespread storm slabs reactive to human triggers. Make conservative terrain choices as you gather information about the bond of the new snow.

Summary

Confidence

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

Weather Forecast

  

FRIDAY NIGHT: Snow; 5-10 cm / Moderate to strong, southwest wind / alpine low temperature -10 / Freezing level valley bottom.

 SATURDAY: Mix of sun and cloud / Light, west wind / alpine high temperature -5 / Freezing level 800 m.

 SUNDAY: Mix of sun and cloud / Moderate, south wind / alpine high temperature -6 / Freezing level 1000 m.

 MONDAY: Snow, 5-10 cm / Moderate, south wind / alpine high temperature -3 / Freezing level 1200 m.

Avalanche Summary

Storm slabs are expected to be reactive to human triggers on Saturday.

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 2-3 avalanches reported on the early November crust in both the North Columbia and neighbouring Glacier National Park region.  

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

Snowpack Summary

Recent storm totals are expected to be around 15-25 cm by Saturday morning. The biggest snowfall amounts are expected to be in the northern half of the region. Storm slabs will likely be widespread in the region. A crust from early November exists down approximately 90-130 cm. This crust has been observed to have weak, sugary facets above and below it. Recent tests on this layer indicate that it may be bonding poorly, and has the potential to be triggered by humans. 

Terrain and Travel

  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.
  • Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Be careful to keep storm day fever from luring you out into bigger terrain features.

Problems

Storm Slabs

An icon showing Storm Slabs

  

Widespread storm slabs are expected to be reactive to human triggers on Saturday.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1.5 - 2.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

A crust from early November exists down about 80-100 cm. This layer has weak, sugary facets above and below it. There are limited observations on this layer right now, however some recent test results suggest that it has the potential to be triggered by humans.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Nov 28th, 2020 4:00PM