Avalanche Forecast

Issued: Dec 18th, 2023 4:00PM

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

Avalanche Canada lbaker, Avalanche Canada

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A buried weak layer remains a concern in the alpine. Use good travel habits to avoid getting caught off guard.

Read our Forecasters' Blog for details on a persistent slab problem in the region

Summary

Confidence

Moderate

Avalanche Summary

No recent persistent slab avalanche activity has been reported but the weak layer continues to be reactive in snowpack tests. These layers are most likely to be reactive to triggering in shallow snowpack areas at higher elevations.

If you go out in the backcountry, please consider sharing your observations on the Mountain Information Network (MIN).

Snowpack Summary

A dusting of snow has buried a layer of surface hoar and sun crust. A prominent rain crust is found 30 to 60 cm deep. While the dry snow above the crust is bonding well, in some areas below the crust is a layer of large weak surface hoar crystals. It may be possible to trigger this surface hoar layer in areas where the crust is thinner and less supportive, with higher-elevation terrain being the most suspect. Typical snowpack depths at treeline are 70 to 110 cm, and taper rapidly below treeline.

Weather Summary

Monday Night

Mainly cloudy with isolated flurries, 2 cm accumulation, alpine wind southwest 30 to 40 km/h, treeline temperature -1 °C, freezing levels drop to 1300 m.

Tuesday

Cloudy with scattered flurries, 2 to 6 cm accumulation, alpine wind southwest 40 to 50 km/h, treeline temperature -3°C, freezing level 1300 m.

Wednesday

Cloudy with isolated flurries, trace accumulation, alpine wind west 30 to 50 km/h, treeline temperature -2°C, freezing level 1500 m.

Thursday

Mainly cloudy with isolated flurries, trace accumulation, alpine wind west 40 to 50 km/h, treeline temperature -2°C, freezing level 1700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Surface hoar distribution is highly variable. Avoid generalizing your observations.
  • Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
  • Early season avalanches at any elevation have the potential to be particularly dangerous due to obstacles that are exposed or just below the surface.

Problems

Persistent Slabs

An icon showing Persistent Slabs

A preserved layer of surface hoar is found down 30 to 60 cm. At higher elevations, the weak layer is not capped by a rain crust and may be reactive to human-triggers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Valid until: Dec 19th, 2023 4:00PM

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