Bulletin d’avalanche

Kootenay Boundary

Mar 1 – 2, 2012Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Sat
Sun
Alpin
4 · Fort
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
    Very Likely
    Taille
    1–5
    Generally lurking below ridgecrests, behind terrain breaks, and in gullies. Wind slabs are very touchy and continued strong winds over the forecast period is expected to overload weaknesses.

  • 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
    Likely - Very Likely
    Taille
    1–4
    Touchy weaknesses within and under the recent storm snow are expected to become more reactive with warm temperatures and new snow load.

Confidence

Fair - Intensity of incoming weather is uncertain for the entire period

Weather Forecast

Friday: Light flurries in the morning increasing throughout the day with 5-10cm possible by nightfall. Strong westerly winds and freezing levels as high as 1000m. Saturday: Another 15-25cm by the end of the day with continued strong westerly winds and freezing levels rising throughout the day to as high as 2000m. Sunday: Continued light flurries with freezing levels dropping throughout the day.

Avalanche Summary

Recent reports include several natural and human triggered soft wind slab and small dry loose snow avalanches in involving the new snow and a recent storm snow weakness. The slabs are generally in the 20-40cm range with avalanches in the Size 1-1.5 range. One report includes skiers on top of a ridge remotely triggering numerous storm slabs up to Size 2 on steep slopes below.

Snowpack Summary

10-30cm of new snow is sitting on surface hoar on shady aspects and a thin sun crust on south aspects. A weak storm snow interface of well-preserved stellars is down approximately 40-50cm and reactive to human triggers on steep shady (cold) slopes at and below treeline. However the main snowpack feature of concern continues to be the surface hoar buried mid-February, which is now down 60-120cm and still giving easy sudden snowpack test results. This persistent weakness is susceptible to remote triggering and has the ability to propagate in low angled terrain, and the overlying slab structure creates the potential for step-down avalanches. Although generally getting deeper and harder to trigger, avalanche professionals throughout the region continue to treat this weakness with extreme caution.

Régions couvertes