Avalanche Forecast

Issued: Dec 28th, 2023 4:00PM

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

Avalanche Canada jpercival, Avalanche Canada

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Uncertainty around buried weak layers is best managed with conservative terrain choices.

Summary

Confidence

Low

Avalanche Summary

There have been very few reports from this region in the past few days.

Last weekend, there were numerous reports of natural and skier-triggered persistent slabs, mainly at treeline, up to size 2. Check out this MIN from Powder King on Saturday and this MIN in Torpy on Friday. We suspect these avalanches ran on one of the surface hoar layers in the top meter of the snowpack.

Natural avalanche activity is expected to trend down, but large human-triggered slabs remain possible.

Snowpack Summary

Recent winds have resulted in extensive wind-affected surfaces in the alpine and treeline. Below treeline, a fresh crust has formed either on or close to the surface.

The mid pack contains several layers of note; a layer of surface hoar down 30 to 50 cm, a significant crust from the early December rain event down around 60 cm and a layer of surface hoar down 70 to 120 cm.

Snowpack depth throughout this region is highly variable and as a result the depths of the above mentioned layers are approximate and could be different than what you find in your riding area.

Weather Summary

Thursday Night

A mix of sun and cloud, no new snow. South alpine wind 50 to 70 km/h. Treeline temperature -1 °C. Freezing level 1400 m. Possible temperature inversion.

Friday

Partially cloudy, no new snow. South alpine wind 40 to 50 km/h. Treeline temperature 3 °C. Freezing level 2500 m. Possible temperature inversion.

Saturday

Mainly cloudy, no new snow. South alpine wind, 20 to 40 km/h. Treeline temperature 1 °C. Freezing level 2000 m. Possible temperature inversion.

Sunday

Cloudy, snow flurries 1-5 cm. South alpine wind, 20 to 40 km/h. Treeline temperature -5 °C. Freezing level 1000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Any steep opening in the trees should be treated as suspect right now.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Use careful route-finding and stick to moderate slope angles with low consequences.

Problems

Wind Slabs

An icon showing Wind Slabs

Recent strong southerly winds have likely formed wind slabs on a variety of aspects on lee features in exposed terrain at treeline and above.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

Buried surface hoar may remain rider-triggerable. This layer is of greatest concern around treeline elevation in areas where a significant crust is not found above it.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 3

Valid until: Dec 29th, 2023 4:00PM