Avalanche forecast

South Coast

Dec 7 – 8, 2021Avalanche Canada
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Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Expect to see slab formation in recent snow due to increases in wind and temperature over the day Tuesday. Watch for signs of instability like shooting cracks or recent avalanches. If triggered, slabs will slide easily over the slippery crust.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Wind and freezing levels are forecast to ramp up Tuesday and it's unclear how this combination will play out in the recent snow. Generally, both have a destabilizing effect on fluffy new snow but in this case, the two might counteract each other to some extent. As snow warms and settles it becomes more difficult for the wind to pick it up and transport it. Given the modest accumulations of snow over the crust, only the deeper wind loaded deposits would be our main concern for triggering avalanches. If you see snow blowing in the wind or fat looking pockets in lee terrain features, raise your guard.

Confidence

Low - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

Monday night: Cloudy. Light to moderate westerly wind. Freezing level climbing to 1000 m.

Tuesday: Flurries around 5 cm. Westerly wind building to strong. Treeline high temperatures around 0. Freezing level 1500 m.

Wednesday: Overnight snow 15-20 cm. Strong southwest wind. Treeline high temperatures around -5. Freezing level 800 m.

Thursday: Isolated flurries. Light to moderate northwest wind. Treeline high temperatures around -5. Freezing level 500 m.

Avalanche Summary

No recent reports.

Snowpack Summary

On Tuesday, rising wind and temperatures influence 10-20 cm of recent snow sitting over a thick, supportive surface crust. A layer of weak, feathery surface hoar crystals was observed growing on the crust prior to the snowfall.

Treeline snow depths in advance of the storm were around 80-100 cm but rain has eroded some of this. Much of treeline and almost all below treeline elevations are still below threshold depths for avalanches.

Terrain and Travel

  • Be carefull around freshly wind loaded features.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Closely monitor how the new snow is bonding to the crust.
  • Keep in mind the crust offers an excellent bed surface for avalanches.
  • Even a small avalanche can be harmful if it pushes you into an obstacle or a terrain trap.

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