Avalanche forecast

Northwest Inland

Dec 18 – 19, 2012Avalanche Canada
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Avalanche danger

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

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Storm slabs might be encountered on steeper slopes with recent new snow. The bigger issue is linked to the wind. Be alert for new and buried wind slabs behind ridges and ribs.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–6
    A deeply buried facet/crust weakness exists. This layer could be triggered by large loads, such as a cornice collapse or a rider digging deeply with a spinning track in a shallow spot on a steep, slope.

Confidence

Fair - Due to limited field observations for the entire period

Weather Forecast

Wednesday: Moderate snowfall with 5-10cm of accumulation, strong southerly winds, and freezing levels in valley bottoms. Thursday: Light snow with only a few centimetres of accumulation, moderate southeasterly winds and freezing levels in valley bottoms. Friday: Mostly cloudy with isolated light flurries, continued moderate southeasterly winds, and freezing levels remaining in valley bottoms.

Avalanche Summary

No recent avalanches have been reported. On Wednesday last week, a snowmobiler triggered a hard wind slab at the Sinclair riding area. It failed on the November crust/facet layer 30 cm above the ground while side hilling. Check out this incident report for more details. This deep crust/facet layer has been the failure plane for a number of large avalanches further to the west and was suspected to have failed at the Hankin-Evelyn area last weekend.

Snowpack Summary

Storm snow instabilities are likely slowly settling and gaining strength. Spotty surface hoar was buried in the upper snowpack, particularly in sheltered treeline areas. New and buried wind slabs are widespread and exist on a variety of alpine and exposed treeline slopes due to variable winds. Of key concern is a November facet/crust layer which can be found near the base of the snowpack. This layer, which is widespread, can be triggered from thin-spot trigger points, or with a heavy load, such as storm slabs stepping down, a cornice fall or a snowmobile track digging a trench. It has the potential for large, destructive avalanches. In general the snowpack depths, and therefore strength is highly variable due to windy conditions this season.

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