Bulletin d’avalanche

Northwest Inland

Jan 10, 2017Avalanche Canada
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Archivé · expiré 10 years ago

Danger d’avalanche

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

Weak, sugary snow at the bottom of the snowpack remains a primary concern. This is especially true in large, steep, and rocky alpine features with variable snowpack depths.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    Forecast strong to extreme winds may redistribute any remaining loose surface snow into fresh wind slabs, adding to an ongoing wind slab problem. Wind slabs may step down to deeper weak layers resulting in surprisingly large avalanches.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3
    In most areas this is a lower probability, high consequence scenario and requires a conservative approach to larger terrain features. Avoid likely trigger spots such as steep and rocky areas with a shallow snowpack.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Tuesday: Clear skies / Moderate to strong northerly winds / Alpine temperatures of -15Wednesday: Clear skies / Moderate northerly winds / Alpine temperatures of -5Thursday: Light flurries / Extreme westerly winds / Alpine temperatures of -12

Avalanche Summary

A large natural slab avalanche was reported from the Babine Range on Sunday. The slab, which ran approximately 200m, was reported to be 50m wide and 50cm deep. The weak layer associated with this avalanche is unknown. Thanks to the individual who submitted the observation via the Mountain Information Network.

Snowpack Summary

10-20 cm of new snow fell last weekend. Observations have been limited, although I suspect these accumulations have likely been shifted into wind slabs at treeline and in alpine. Snow depth at treeline varies from about 1 m in most areas to 2 m in deeper snowpack areas in the south and west of the region, and up to 250 cm in the alpine. The shallow snowpack areas mostly consist of weak facetted or sugary grains beneath hard slabs. These hard slabs may produce surprisingly long fractures resulting in large avalanches, and in some instances they may step down to weak snow crystals near or at the ground. In addition to the facets, a thick layer of buried surface hoar may be found 30-40 cm below the surface. There is another persistent weakness that formed during the early December cold snap which is now about 50-70 cm deep. A crust from mid-November may be lurking close to the ground nestled in amongst the facets.

Régions couvertes