Avalanche forecast

Northwest Coastal

Dec 16, 2017Avalanche Canada
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Archived · expired 9 years ago

Avalanche danger

Sun
Mon
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

Saturday is storm day! Avoid avalanche terrain during periods of heavy loading from rain, new snow and wind.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely - Certain
    Size
    1–3
    New storm slabs will likely build through the forecast period on all aspects and elevations. Wet loose avalanches may occur from steeper terrain features below treeline.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–3
    Weak layers buried near the base of the snowpack can't be dismissed while new snow or rain load the surface.

Weather Forecast

Saturday: Snow amounts 20-30 cm. Alpine temperatures -2 and freezing levels 800 m. Ridgetop winds strong from the southwest.Sunday: Cloudy with sunny periods and new snow amounts 3-10 cm. Alpine temperatures -3 and freezing levels 600 m. Ridgetop winds light with strong gusts from the southwest.Monday: Cloudy with isolated flurries. Alpine temperatures -3 and freezing levels 600 m. Ridgetop winds light from the southwest.Check out the Mountain Weather Forecast for more detail.

Avalanche Summary

On Friday, wet slab avalanches size 1-2 were reported from steep terrain where the ground cover consists of smooth rock slab features. These avalanches went to ground. Widespread natural avalanche activity expected through the forecast period with new rain, snow and wind.

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Snowpack Summary

Up to 30 mm of precipitation fell as a rain and saturated the snowpack up to 800 m on Thursday. On Friday, the freezing levels dropped and the new snow is currently building storm slabs on all aspects and elevations. Below the surface sits a well-settled snowpack overlying several layers of interest. Down 70-100 cm you'll likely find a 5-10 cm thick crust which was buried on November 23 and in some areas, a feathery surface hoar layer down 50-60 cm producing moderate snowpack test results. The widespread crust/facet interface that was buried at the end of October can now be found 100-200 cm deep and exists region wide.

Regions covered