Avalanche Forecast

Issued: Dec 17th, 2024 4:00PM

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

Avalanche Canada Avalanche Canada, Avalanche Canada

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UPDATED AT 6:35 AM: Danger will increase at higher elevations, where the storm delivered more snow than rain.

Summary

Confidence

Moderate

Avalanche Summary

Several small natural slab avalanches were observed in steep terrain at treeline over the weekend.

If you are going out in the backcountry, please consider sharing your observations to the Mountain Information Network (MIN).

Snowpack Summary

By early morning on December 18th 50 to 90 mm of precipitation could have fallen. This will initially fall as snow in the afternoon of the 17th and switch to rain overnight before switching back to snow by early morning on the 18th. The result will be dry snow over wet or moist snow. This precipitation will also be accompanied by strong southerly winds forming deeper deposits on northerly aspects.

A prominent crust is down 60 to 100 cm at treeline. A layer of surface hoar may be found in sheltered areas at treeline at this depth but it’s distribution is uncertain.

Snow depths taper substantially below 1000 m.

Weather Summary

Tuesday Night

Cloudy with 40 to 60 mm of precipitation expected. 40 to 70 km/h south ridgetop wind. Freezing level rising throughout the night to 2200 m.

Wednesday

Cloudy in the early morning and clearing in the afternoon. Up to 5 cm of snow in the early morning. 40 km/h southwest ridgetop wind shifting to 10 to 20 km/h west by early morning. Freezing level falling throughout the day to 1200 m.

Thursday

Cloudy with around 5 mm of rain expected. 40 to 60 km/h southeast ridgetop wind. Freezing level rising to 2300 m.

Friday

Increasing cloud throughout the day. 30 to 40 km/h southeast ridgetop wind. Freezing level rising to 2800 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be alert to conditions that change with elevation and sun exposure.
  • Don't let storm day fever lure you into consequential terrain.
  • Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.

Problems

Storm Slabs

An icon showing Storm Slabs

Reactive storm slabs will have formed overnight. The largest and most reactive slabs will likely be found in the alpine where all or most of the expected precipitation will have fallen as snow. Reactivity could increase with solar input.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 2.5

Valid until: Dec 18th, 2024 4:00PM

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