Avalanche Forecast

Issued: Feb 2nd, 2021 4:00PM

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

Avalanche Canada kdevine, Avalanche Canada

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Although the storm has subsided, human triggered avalanches remain likely, especially in wind loaded areas. 

Keep in mind that a persistent weak layer is now buried up to 100 cm. Avalanches on this layer will become harder to predict, so a conservative approach is important.

Summary

Confidence

Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast. Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

TUESDAY NIGHT - Mainly cloudy with a few flurries / light southwest wind, switching to light north wind / alpine low temperature near -10 

WEDNESDAY - Sunny with cloudy periods / light north wind / alpine high temperature near -9

THURSDAY - Mainly cloudy with a few flurries, / moderate west wind / alpine high temperature near -7 

FRIDAY - A mix of sun and cloud / light to moderate west wind / alpine high temperature near -5

Avalanche Summary

Avalanches are expected to remain easy to trigger on Tuesday in many areas, especially in wind loaded terrain at higher elevations.

There have been reports of size 1-2 natural, human and explosives triggered avalanches every day since Saturday. Many of these avalanches have failed on the recently buried persistent weak layer.

Snowpack Summary

50-100 cm of recent fresh snow sits on a persistent weak layer that consists of facets at upper elevations, surface hoar in sheltered areas, a melt-freeze crust below 1900 m, and a sun crust on south-facing slopes. There could be more than 100 cm on this layer in wind loaded areas.

A crust from early December may be found around 200+ cm deep in the snowpack. In shallow rocky areas, it may still be possible to trigger this layer. In deeper snowpack areas, it appears to be unreactive.

Terrain and Travel

  • Keep in mind that human triggering potential persists as natural avalanching tapers off.
  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.

Problems

Storm Slabs

An icon showing Storm Slabs

Recent fresh snow combined with strong southerly winds has formed reactive storm slabs in many areas, especially wind loaded terrain features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

50-100 cm of snow sits on a widespread weak layer that consists of facets, surface hoar, or a crust depending on location. Avalanches may propagate widely on this layer.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Feb 3rd, 2021 4:00PM