Avalanche Forecast

Issued: Feb 21st, 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.

Avalanche Canada JSmith, Avalanche Canada

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The new snow may be more reactive than expected; especially on slopes where it has been wind loaded and is sitting on a layer of fragile surface hoar.

Summary

Confidence

Moderate - Uncertainty is due to the timing, track, & intensity of the incoming weather system.

Weather Forecast

FRIDAY NIGHT: 5-10 cm. snow, strong southwest wind, alpine temperature -7 C, freezing level below valley bottom.

SATURDAY: 3-5 cm snow, moderate west wind, alpine temperature -3 C, freezing level 1100 m.

SUNDAY: 5-10 cm. snow, light to moderate south wind, alpine temperature -4 C, freezing level 800 m

MONDAY: Cloudy with potential flurries; 0-3 cm, light west wind, alpine temperature -4 C, freezing level 800 m

Avalanche Summary

Numerous cornice falls over the last couple days had a variety of results. They mostly only entrained recent storm snow but a few did trigger slab avalanches up to size 2.5. Additionally, several skier triggered slab avalanches up to size 1.5 were reported primarily in wind affected terrain. 

Snowpack Summary

Clear and sunny skies have formed new surface hoar (size 3-10 mm.) on all but solar aspects where a new sun crust has been formed. This new interface will need to be carefully monitored as it gets buried. New snow falling on this layer will be more reactive than previous storms where the new snow did not fall on a persistent weak layer. The early February rain crust is another prominent layer in the upper snowpack that requires monitoring, though there have been no recent avalanches on this layer. The lower snowpack is generally well settled and strong.

Terrain and Travel

  • Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
  • Be alert to conditions that change with elevation, aspect and exposure to wind.
  • Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.
  • Cornice failure may trigger large avalanches.

Problems

Storm Slabs

An icon showing Storm Slabs

The new snow may be more reactive than expected; especially on slopes where it has been wind loaded and is sitting on a layer of fragile surface hoar.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Feb 22nd, 2020 5:00PM