Bulletin d’avalanche

Northwest Coastal

Feb 25 – 26, 2016Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
1 · Faible
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Points saillants

New snow and strong winds are expected to continue adding to the widespread wind slab problem.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    Recently formed wind slabs are lurking on many alpine and treeline slopes. Incoming snow, wind and rising temperatures may create a new storm slab problem above older wind slabs.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–6
    A storm slab or wind slab could step down and trigger a deeply buried weak layer, creating a surprisingly large avalanche.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

The first of two cold fronts is expected to bring 10-15 cm snow on Friday, with strong southerly winds and the freezing level rising to around 1200 m. There is a lull on Saturday before the second front brings around 15 cm and more strong winds on Sunday.

Avalanche Summary

Size 1-2 wind slabs were triggered naturally and by skiers on Wednesday, mostly at alpine and treeline elevations.

Snowpack Summary

Recent strong winds have created wind slabs on a variety of slopes at alpine and treeline elevations. Incoming snow will bury a thin sun crust on sunny aspects and surface hoar in isolated sheltered and shady locations. 40-100 cm of snow sits above a melt freeze crust buried around February 12th. This crust extends up to about 2000 m. Although the snow above is bonding well to this crust in most places, recent snow pit tests northwest of Terrace produced failures on or in facets just below this layer under moderate to hard loads. Below this, a layer of surface hoar buried late in January remains a concern in thin snowpack areas in the east and north of the region. The snowpack in these areas may also sit on a weak base of facets near the ground. Below treeline, the snowpack depth is lean to non-existent in the south. In the north, the below treeline snowpack is generally considered strong.

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