Bulletin d’avalanche

Kootenay Boundary

Mar 7 – 8, 2014Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

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

Be alert to conditions that change with elevation.  A saturated snowpack means avalanches have the potential to entrain significantly more mass than usual.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    3–6
    The early Feb weak layer still remains reactive in some areas and has the potential to produce large, destructive avalanches. Warm temperatures and the load of the new snow may 'wake up' this weak layer and very large natural avalanches are possible.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–4
    Warm temperatures are encouraging the settlement of the storm snow into a  soft slab that overlies a variety of potentially weak surfaces. Moderate to strong SW winds have formed stiff wind slabs in lee features.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–4
    Bellow1800m rain has saturated the upper snowpack. Continuing warm temperatures mean loose wet avalanches are still possible.

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Synopsis: A series of fronts is sliding down the BC coast. The warm front should pass over the Southern Interior on Saturday evening, followed by the cold front Sunday. Expect 20-40mm of precipitation before conditions dry out on Monday.Tonight and Saturday: Snow or rain starting late in the day / Strong SW winds / Freezing levels 2100mSunday: Snow or rain / Strong W winds / Freezing levels 2200mMonday: Flurries / Light NW winds / Freezing levels 1400-1700m.

Avalanche Summary

A cycle of large natural, accidental and controlled storm and wet slab avalanche occurred Thursday in response to heavy loading and mild temperatures. These avalanche were reported to be entraining significant mass through their track, trenching down the the midpack crust or through to ground.A large persistent slab avalanche was remotely triggered by a skier on the the early February weakness. This is a good reminder that although there has not been much activity on this layer for a while it is still a lingering problem in the snowpack. Natural activity tapered off on Friday as conditions dried out briefly.

Snowpack Summary

The recent storm snows are rapidly settling into a soft slab. This snow sits above a variety of old surfaces. A layer of facets can be found on north aspects with a sun crust on many south facing slopes. Recent rains up to 1800m are saturating the upper snowpack. At elevations above the freezing level sustained SW winds have have formed winds labs in lee features. The midpack is broken by a widespread persistent weak layer found down 90 to 120cm. The form of this week layer varies from surface hoar to a sun crust and/or facets.  It can be found at all elevations, on all aspects and is still a concern.

Régions couvertes