Avalanche Forecast

Issued: Dec 9th, 2021 4:00PM

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

VIAC astclair, VIAC

Stay alert to changing conditions. Avalanche hazard will increase at upper elevations as snow accumulates. Dial back terrain if you are seeing 20 cm of new snow.

Summary

Confidence

Moderate - We are confident the likelihood of avalanche will increase with the arrival of the forecast weather.

Weather Forecast

A fast-moving storm with intense snowfall and fierce wind moves in Friday 

Thursday night: Partly cloudy, light west wind, treeline temperatures dropping to -5 C, freezing level dropping to 500 m.

Friday: Cloudy, 5-15 cm of snow starting mid-morning as a potent storm moves in, wind becoming southwest and strong, treeline temperatures rising to -1 C by end of day, freezing level rising to 800 m.

Saturday: Cloudy, 30-60 cm of snow expected to accumulate overnight and into the morning, strong southwest wind, treeline temperatures rising to near 0 C overnight and dropping to -4 C by midday, freezing level rising to 1300 m overnight during heaviest precipitation and dropping to 500 m by end of day. 

Sunday: Mainly cloudy, 5-15 cm of snow, moderate southwest wind, treeline temperatures near -4 C, freezing level rising to 600 m. 

Avalanche Summary

No recent avalanche activity has been reported. 

Snowpack Summary

A potent storm moves in Friday bringing 5-15 cm of new snow and strong southwest wind by late afternoon. This is expected to build increasingly reactive storm slabs at upper elevations. 

We suspect there may be surface hoar or facets above the early December crust that could present a persistent slab problem with rapid loading from the incoming storm. Send us your observations of what is above the crust where you are travelling using the Mountain Information Network

Recent indications of the region's snowpack suggest that snow depths in the alpine are 150- 200 cm. At treeline, snow depths taper dramatically to 60-120 cm. Below treeline is below the threshold for avalanches.

Terrain and Travel

  • Watch for changing conditions today, storm slabs may become increasingly reactive.
  • Storm slab size and sensitivity to triggering will likely increase through the day.
  • Dial back your terrain choices if you are seeing more than 20 cm of new snow.

Problems

Storm Slabs

An icon showing Storm Slabs

New snow is expected to rapidly accumulate on Friday, accompanied by strong southwest winds and a gradual rise in temperature. Anticipate the development of a touchy, widespread storm slab problem as snow accumulates. 

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 10th, 2021 4:00PM