Bulletin d’avalanche

Kootenay Boundary

Mar 8 – 9, 2012Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–4
    Generally lurking below ridge crests, behind terrain breaks, and in gullies. Wind slabs are touchy and likely to stay that way with Fridays continued strong SW winds.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–6
    Persistently weak buried surface hoar demands continued diligence and conservative decisions. The potential for remote triggering, step down avalanches, and wide propagations, makes this weakness particularly tricky to predict.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Formally touchy weaknesses within the recent storm have now become less reactive, but remain a concern on convex & unsupported features.

Confidence

Fair - Intensity of incoming weather is uncertain on Saturday

Weather Forecast

Friday: Dry for most the morning. Cold front passes through the region in the afternoon, delivering 10 - 15 cm overnight. Freezing level tops out around 1600m Friday afternoon, dropping in the evening. Winds out of the SW, light below treeline, Strong at ridge top. Saturday: Snowfall will continue through the day, I expect total daytime accumulations to be 10 - 15 cm. Freezing level tops out around 1500m again on Saturday. Winds Mod SW near treeline, Mod to Strong SW near ridge top. Light snowfall continues through the night and into Sunday. Light snowfall is still in the picture Sunday which should result in another 10 - 15 cm by sunrise Monday.

Avalanche Summary

On Wednesday a skier triggered a size 1.5 avalanche just north of the forecast region failing on the mid Feb surface hoar, down 70 cm below the snow surface. No other significant avalanche observations were reported Wednesday, but, neighboring regions continue to report large natural and human triggered avalanches. On Tuesday, avalanches from the west side of the region were smaller and seem to be limited to the storm snow. In the east, where more storm snow fell avalanches were much larger. For example near Wyndell a large natural slide buried a sled access road near valley bottom. Some remotely triggered and accidentally triggered slides reported by skiers that were 70 to 100 cm deep.

Snowpack Summary

Recent storm snow amounts were approximately 40 cm in the east and 10 cm in the west, with the snow line at approximately 1600 m. The Valentines day surface hoar layer is now buried beneath as much as 120 to 140 cm! Stability tests show the deep layers are hard to trigger but there's huge potential for propagation.

Régions couvertes