Bulletin d’avalanche

Northwest Coastal

Dec 14 – 15, 2015Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

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Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    Wind and snow forecast for Monday night will form new wind slabs in the alpine and at treeline. Watch for conditions that change with elevation, and use extra caution around ridge crests, gullies and convexities.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–4
    Human triggered avalanches on a layer of buried surface hoar have become less likely. However, avalanches at this interface could be destructive in nature. Dig down and test for this weakness before committing to any steep lines.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Tuesday

Weather Forecast

A Pacific frontal system will slide through the region on Monday night and Tuesday bringing up to 15cm of snow and strong to extreme westerly winds. A dry ridge of high pressure will develop for Wednesday and early Thursday delivering mainly clear skies and moderate northwesterly winds. Light snowfall is forecast for Thursday afternoon. Freezing levels may rise to 500m with the passage of the frontal system, and then drop to valley bottom on Wednesday and Thursday. For a more detailed weather overview, please check-out our Mountain Weather Forecast at: avalanche.ca/weather

Avalanche Summary

In recent days small pockets of wind slab were observed failing naturally with minimal propagation in the lee of alpine ridge crests. Wind and snow forecast for Monday night and Tuesday will likely spark a new round of wind slab activity in the alpine and at treeline.

Snowpack Summary

Up to 15cm of new snow and strong westerly winds on Monday night are expected to form new wind slabs at treeline and in the alpine. Up to a meter below the surface you may find a weak layer of buried surface hoar. In some areas, this layer may be primed for human triggering and wide propagations while in other areas it is non-existent or has gained significant strength. Due to the variable nature of this weak layer, I'd dig down to test for it before committing to any steep lines. I'd also be increasingly cautious on sheltered slopes at or below treeline.

Régions couvertes