Bulletin d’avalanche

North Columbia

Dec 9 – 10, 2019Avalanche Canada
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Archivé · expiré 7 years ago

Danger d’avalanche

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

Points saillants

There is uncertainty with the reactivity of several buried weak layers. Best to adopt a conservative approach while the snowpack adjusts to the increased load from recent snowfalls.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3

    There is a lot of uncertainty associated with the reactivity and distribution of a surface hoar/crust layer buried 80-120 cm. This layer is most likely found in sheltered openings around treeline and below.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    30-60 cm of new snow accumulating late last week has formed a reactive storm slab. In some areas this may be sitting on a layer of weak surface hoar

Confidence

Moderate - Uncertainty is due to the complexity of the snowpack’s structure.

Weather Forecast

Sunday: Mainly clear with cloudy periods, alpine temperature -9, moderate northwest wind.

Monday: Mix of sun and clouds, alpine temperature -7, moderate north wind.

Tuesday: Mix of sun and cloud, alpine temperature -8, light northwest wind.

Wednesday: Cloudy with flurries, alpine temperature -8, light southwest wind.

Avalanche Summary

Reports from Friday and Saturday indicate skier triggered and natural storm slab avalanches size 1-2 on all aspects. There were also a few reports of persistent slab avalanches failing on a layer of surface hoar down 80-120 cm at treeline elevations over the past several days. At least one of these was remotely triggered (from a distance). Additionally there reports of explosive triggered avalanches to size 3 in the trans Canada highway corridor on Friday.

Snowpack Summary

30-60 cm of new snow from late last week has covered a layer of feathery surface hoar that has been found at all elevations. A thick layer of faceted crystals, previously wind-affected surfaces, and/or surface hoar in sheltered areas (around treeline and below) is now 50-90 cm below the surface.

An additional layer of surface hoar may be found in sheltered areas around treeline down 70-120 cm. In some areas this may sitting on a thin crust.

A variety of crusts from late October are buried deeper in the snowpack.

Régions couvertes