Avalanche Forecast

Issued: Dec 6th, 2021 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Avalanche danger will gradually increase in wind-affected terrain this week. 

Summary

Confidence

Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.

Weather Forecast

MONDAY NIGHT: Clear skies, no precipitation, light wind from the west, treeline temperatures around -15 C.

TUESDAY: Increasing cloud throughout the day, no precipitation, light to moderate wind from the southwest, treeline temperatures warm to -10 C.

WEDNESDAY: 10-25 cm of low density snow, moderate wind from the west, treeline temperatures around -8 C.

THURSDAY: Mostly cloudy skies with some light flurries, light wind from the west, treeline temperatures around -10 C.

Avalanche Summary

Over the weekend there were several reports of small (size 1) avalanches in the recent snow above the crust. These included a mix of stiffer wind slabs and softer dry loose avalanches. One large (size 2) naturally-triggered wind slab was observed on a steep south-facing slope in the alpine.

There is still visible evidence of a widespread avalanche cycle from the Dec 1st atmospheric river.

Snowpack Summary

Up to 25 cm of low density snow covers a crust, which has been exposed in open terrain. At treeline and above, pockets of wind slab up to 40 cm deep are found in lee features, with fun powder in protected areas and depressions.

The snowpack is generally well-consolidated below the surface crust. The mid-November crust is found down 70-150 cm with some faceting below the crust. This feature disappears above 1900 m and does not appear to be problematic at this point.

Snowpack depths range from 120-250+ cm at treeline and above. The snowpack decreases rapidly below 1600 m.

Check out our latest Forecaster Blog here.

Terrain and Travel

  • Be carefull around freshly wind loaded features.
  • Use caution when approaching steep and rocky terrian.
  • Wind slabs may be poorly bonded to the underlying crust.
  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.

Problems

Wind Slabs

An icon showing Wind Slabs

Wind speeds will increase as a weak frontal system crosses the region on Tuesday. The wind will likely form some unstable slabs on the downwind side of ridges. Wind slabs could be poorly bonded to the underlying crust.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 7th, 2021 4:00PM