Avalanche Forecast

Issued: Dec 17th, 2023 4:00PM

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

Avalanche Canada jpercival, Avalanche Canada

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New wind slabs continue to bury weak layers, creating a complex avalanche hazard. Monitor for signs of instability and stick to low-consequence terrain.

Summary

Confidence

Moderate

Avalanche Summary

A size 1.5 storm slab avalanche was triggered by a skier on Thursday near Terrace. This avalanche failed on buried surface hoar, 30 cm deep from a feature near ridge crest.

On Wednesday, a large avalanche cycle occurred. Natural and explosive triggered avalanches avalanches, up to size 3, were reported throughout the region. These avalanches mostly occurred on lee slopes or lee features. One of these avalanches was reported to have failed on buried surface hoar, 50 cm deep.

Snowpack Summary

New snow amounts of 15 cm on Sunday has been redistributed by southwest winds. This will be added to the 20 to 45 cm of snow that fell earlier in the week which was also accompanied by strong south and southwesterly winds.

A buried layer of weak, feathery surface hoar crystals can now be found 25 to 50 cm deep. While another layer of buried surface hoar may exist deeper in the snowpack, roughly 55 to 95 cm below the surface.

The remaining mid and lower snowpack contains several crusts from early in the season that are generally well-bonded to the surrounding snowpack.

Currently, the height of snow is highly variable and decreases significantly at lower elevations.

Weather Summary

Sunday Night

Cloudy, 5 to 10 cm accumulation, ridgetop winds southwest 30 km/h, treeline temperature -5 °C. 

Monday

Cloudy, 5 to 10 cm accumulation, ridgetop winds southwest 30 to 50 km/h, treeline temperature -2 °C.

Tuesday

Cloudy with late day clearing, 10 to 15 cm accumulation, ridgetop winds southerly 30 to 40 km/h, treeline temperature -3 °C.

Wednesday

Cloudy, 5 cm accumulation, ridgetop winds southerly 70 km/h, treeline temperatures -3 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid areas where the snow feels stiff and/or slabby.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Watch for fresh storm slabs building throughout the day.

Problems

Wind Slabs

An icon showing Wind Slabs

Wind slabs have likely formed from southwest winds. Wind slabs may be more reactive where they have buried weak layers 30 to 100 cm deep.

In sheltered areas expect to find storm slabs that may be reactive to human triggering.

Aspects: North, North East, East, South East, South, West, North West.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs

At treeline elevation, the sensitivity of this avalanche problem may rise with additional snowfall.

Aspects: All aspects.

Elevations: Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Dec 18th, 2023 4:00PM

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