Bulletin d’avalanche

Purcells

Dec 31, 2014 – Jan 1, 2015Avalanche 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
2 · Modéré
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Points saillants

Tricky and variable avalanche conditions.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–4
    Recent strong winds have left wind slabs behind on a variety of slopes.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–5
    A buried surface hoar/ crust layer demands respect. It has been easy to trigger persistent slabs with light loads (like a person). This layer is down about 30-50 cm in most areas, but may be deeper where wind slabs have developed.

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

Snow is expected to begin on Thursday and become more intense overnight and into Friday (5-10 cm by Friday afternoon). Winds are forecast to be moderate from the SW to NW. Freezing level at valley bottom. Snowfall becomes light on Saturday.

Avalanche Summary

Explosives control on Tuesday produced several avalanches up to size 3. Some of these failed on persistent weak layers, while others only involved surface snow. Natural wind slabs were also observed near ridge tops over the last couple of days.

Snowpack Summary

Some areas may have a thin layer of surface hoar that was buried on December 27th and now has about 5-10 cm of light dry snow above. The recent snow may have been transported into wind slabs by strong northerly or moderate southerly winds. A persistent surface hoar/crust weak layer from mid-December is now down about 40-60cm. Recent snowpack tests show moderate pops type results here, indicating the potential for avalanches to propagate on this layer. The persistent slab problem is widespread across the region and is not expected to improve quickly. A deeper crust/facet layer which formed early in the season may still be triggerable from thin or rocky snowpack areas.

Régions couvertes