Avalanche Forecast

Issued: Feb 3rd, 2022 4:00PM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is below threshold. Known problems include Wind Slabs.

Avalanche Canada ahanna, Avalanche Canada

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Avalanche danger will increase as the wind picks up. We have uncertainty around the timing of the wind, but once it starts to blow, deep and reactive wind slabs are likely to trigger naturally as they form. 

Summary

Confidence

Low - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.

Weather Forecast

Thursday night: 5-10 cm of low density snow with moderate SW wind. Alpine temperatures near -15.

Friday: Continued snow flurries 5-10 cm. SW wind building to strong. Alpine temperature near -15. 

Saturday: Continued snow flurries 5-10 cm. Strong SW wind. Alpine temperature warming to -5.

Sunday: Continued snow flurries 5-10 cm. Strong SW wind. Alpine temperature near -5.

Avalanche Summary

On Wednesday numerous size 1 dry loose and soft slabs ran naturally and were easily reactive to skier triggering. On the Alaska side, strong outflow winds made for touchy avalanche conditions, with natural releases running to the road. We are expecting similar conditions in White Pass as the wind picks up.

Snowpack Summary

Flurries continue to accumulate over 45 cm of low-density snow from Wednesday. As the wind picks up on Friday, all that new snow will likely be transported into wind slabs in lee terrain features. These fresh slabs will likely be reactive due to a poor bond to underlying surfaces including surface hoar on sheltered northerly aspects and hard slab in wind-affected areas.

In shallow snowpack areas a layer of loose facets sits at the bottom of the snowpack.

Terrain and Travel

  • Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
  • Avoid all avalanche terrain during periods of strong wind.
  • Wind slabs are most reactive during their formation.
  • Avoid exposure to overhead avalanche terrain, avalanches may run surprisingly far.

Problems

Wind Slabs

An icon showing Wind Slabs

Upwards of 45 cm of low density snow sits available for wind transport. As winds build, the recent snow will likely be transported into leeward terrain features and stiffened into slabs. These slabs are expected to be highly reactive due to a poor bond to underlying surfaces.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 2

Valid until: Feb 4th, 2022 4:00PM