Bulletin d’avalanche

Kootenay Boundary

Dec 21 – 22, 2018Avalanche Canada
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Archivé · expiré 8 years ago

Danger d’avalanche

Sun
Mon
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

A weak layer exists in our snowpack at a depth where humans can still trigger it. It is a good time to remain conservative with your terrain selection.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    Recent strong winds from variable directions have produced touchy wind slabs in lee terrain features. Be cautious near ridges on all aspects.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3
    A weak layer buried around 50 to 100 cm is the primary concern. Expect to find it on all aspects and all elevations, except for the most exposed of terrain where wind or sun may have altered it. This weak layer has recently produced large avalanches.

Confidence

High.

Weather Forecast

FRIDAY NIGHT: Clear, freezing level below valley bottom. SATURDAY: Sunny with a few clouds, moderate southwest winds, alpine temperature -9°c, freezing level below valley bottom. SUNDAY: Cloudy with light snowfall, accumulation 5cm, moderate southwest winds, alpine temperature -6°c, freezing level below valley bottom. MONDAY: Partly cloudy, light southwest winds, alpine temperature -7°c, freezing level below valley bottom.

Avalanche Summary

Large (size 2 to 3) slab avalanches were triggered naturally, by skiers, and explosives on Tuesday through Thursday. The avalanches were generally 50 to 100cm deep and either within the storm snow or on the weak layer described in the snowpack discussion. Storm slabs have stepped down to the deeper weak layer.

Snowpack Summary

Strong winds from first the south and then the northwest have redistributed the recent storm snow, producing wind slabs in lee terrain features at all elevations. Beneath this, around 50 to 100 cm of snow is poorly bonded to a rain crust and a weak layer of feathery surface hoar and sugary facets. Avalanche activity, remote triggering, and snowpack test results tell us that it is a critical layer. It is best to travel extremely cautiously with this layer in the snowpack. The lower snowpack is well-settled.

Régions couvertes