Avalanche Forecast

Issued: Dec 22nd, 2020 4:40PM

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

Marcus Waring,

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Give the new snow time to settle and be mindful of the reverse loading that occurred during the storm. New snow may stress buried weak layers. Our increasingly complex snowpack warrants a cautious approach over the holidays.

Summary

Weather Forecast

Tonight: Trace amounts of snow with moderate North wind. Freezing level valley bottom.

Wednesday: Cloudy with sunny periods. Moderate Westerly wind. Possible alpine temperature inversion at Cameron Lake.

Thursday: Sunny With cloudy Periods. Moderate Westerly wind. Alpine temperature inversion at Cameron Lake.

Snowpack Summary

30cm of new snow arrived with a moderate Northerly wind causing reverse loading. New snow has a rain crust below 1900m within the storm slab. These new storm slabs sit over a thick persistent slab which overlies the Dec 9th melt freeze crust. The mid snowpack is well consolidated with a ice crust forming the base of the snowpack.

Avalanche Summary

Storm conditions obscured Alpine limiting observations.

No avalanches observed at the treeline elevation at Cameron Lake.

Treeline snow depth at Cameron lake up to 1.5m with amounts tapering quickly at lower elevations and in other areas of the Park.

Confidence

Problems

Storm Slabs

An icon showing Storm Slabs

Storm slabs are the primary problem Wednesday. Storm slabs may be more reactive on northerly aspects where wind has stiffened slabs. We expect this problem to transition to wind slab by the end of the week.

  • If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
  • Keep an eye out for reverse loading created by N-NE winds.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Wind Slabs

An icon showing Wind Slabs

Variable wind direction over the forecast period means wind slab may pop up in unexpected areas. Look for wind effect at the surface and avoid exposure terrain with high consequence.

  • Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

Old wind slab sits on top of the Dec 9th melt freeze crust making it a persistent slab The Dec 9th crust is buried 20-80cm deep at Cameron Lake. This layer has not been reactive yet, but there is a chance that the new snow will stress this weakness.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

1 - 3

Valid until: Dec 25th, 2020 4:00PM