Bulletin d’avalanche

Purcells

Dec 24 – 25, 2014Avalanche Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Tricky avalanche conditions exist out there, use a conservative approach and make good choices. Happy Holidays everyone!

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    A thick storm slabs sits over a predominant surface hoar layer which is very touchy to skier and rider triggers.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–5
    The new snow load continues to build and this could reawaken the Nov 9 layer at the bottom of the snowpack. Shallow avalanches running on the surface hoar may also trigger this layer.

Confidence

Good

Weather Forecast

By Thursday an upper ridge will build behind the cold front bringing cooler conditions with mostly cloudy skies and light precipitation amounts. Light northwest winds and alpine temperatures dropping to -15 will persist through the forecast period. Freezing levels at valley bottom.

Avalanche Summary

On Tuesday, reports from the field were still indicating that the buried surface hoar layer is very touchy to skier/ rider triggers and numerous avalanches size 1-2.5 were reported. With a thicker slab overlying this touchy layer, I don't expect things to improve over the holiday period and suspect this layer is primed for human triggers.

Snowpack Summary

New snow 10-20 cm fell Tuesday night, with southern locations seeing the higher amounts. Moderate SW winds accompanied the snowfall adding more load to the upper snowpack. This brings storm snow totals 30-80 cm above a very touchy surface hoar layer that was buried mid-December. Below 2100 m this storm slab sits on a thick, solid crust that has been acting as a perfect sliding layer. Storm slabs will be very touchy to the weight of a skier/ rider, especially in wind effected areas. A hard rain crust with facets from early November is buried over 1 m down and may be reactive to light loads in some locations.

Régions couvertes