Avalanche Forecast

Issued: Dec 15th, 2020 4:00PM

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

Avalanche Canada kdevine, Avalanche Canada

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Fresh snow and moderate southwest winds have likely formed storm slabs that sit on a weak layer of surface hoar in many areas. Use extra caution in wind loaded areas.

Summary

Confidence

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

Weather Forecast

TUESDAY NIGHT - Cloudy with isolated flurries / southwest wind, 20-40 km/h / alpine low temperature near -6

WEDNESDAY - Cloudy with scattered flurries, 5 cm / southwest wind, 15-30 km/h / alpine high temperature near -4

THURSDAY - Flurries, 5-10 cm / southwest wind, 15-30 km/h / alpine high temperature near -3

FRIDAY - Flurries, 5-15 cm / southwest wind, 15-30 km/h / alpine high temperature near -5

Avalanche Summary

On Tuesday, there were reports of numerous natural and human triggered avalanches, size 1-1.5.

Over the last week, avalanche activity has mainly been limited to size 1 skier triggered storm/wind slabs running on the recently buried crust. This great MIN from Friday near Nelson includes a photo of an accidental wind slab.

Please submit your observations to the Mountain Information Network (MIN). Photos are especially helpful! Thank you so much for all the great MINs submitted so far!

Snowpack Summary

10-15 cm of new snow sits on a layer of surface hoar in many areas.

A crust that was buried about a week ago is now down 20-25 cm.

At upper elevations, moderate to strong southwest wind has likely blowing the new snow into fresh slabs that may be reactive to human triggers.

The early November crust is sitting about 10-30 cm up from the ground. There is a late November crust in the midpack in some places as well. Uncertainty with these crusts exists due to limited observations, but there haven't been any recent avalanches reported on these layers in this region.

Snowpack depths vary with elevation, treeline averages between 50-100 cm. 

Terrain and Travel

  • Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
  • Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
  • Keep in mind the crust offers an excellent bed surface for avalanches.

Problems

Storm Slabs

An icon showing Storm Slabs

Fresh snow with southwest winds are forming storm slabs that rest on a weak layer of surface hoar. These slabs will likely be the most reactive in wind loaded areas.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 16th, 2020 4:00PM