Avalanche forecast

Northwest Coastal

Feb 1 – 2, 2012Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–7
    Widespread due to strong, shifting winds and large amounts of snow available for transport, but are generally lurking below ridgecrests, behind terrain features and in cross-loaded gullies. They can fail as very large, destructive avalanches.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–6
    Large storm slab avalanches have been occurring for the past week and are expected to continue with heavy loading from rain, snow, and wind.

Avalanche Summary

Warm temperatures and light to moderate precipitation resulted in several low-elevation natural storm slab avalanches up to Size 2. Explosive control on Tuesday produced numerous 40-60cm thick wind slab avalanches up to Size 2.5 with wide propagation on all aspects in the alpine. Several 100-150cm thick slab avalanches up to Size 3.5 were also triggered.

Confidence

Good - -1

Weather Forecast

Thursday: Heavy precipitation with up to 60mm expected. Extreme southerly winds and freezing levels as high as 1200m. Friday and Saturday: Light to moderate precipitation continues throughout the period, with some breaks, all in a moderate southwest flow.

Snowpack Summary

Total snowpack depths are at new record levels for this time of year. Recent warm temperatures helped settle storm snow into a touchy surface slab at lower elevations. Other weaknesses within and under (Jan. 20th facets) the 150+cm of recent storm snow create the potential for step-down avalanches, but things seem to be settling rapidly. Strong winds associated with recent storms means large weak wind slabs and cornices on lee and cross-loaded terrain. Most snowpack concerns are limited to the surface layers, however large triggers such as cornice falls and smaller avalanche stepping-down could affect deeper weaknesses.

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