Bulletin d’avalanche

Purcells

Mar 1 – 2, 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
    1–4
    Generally lurking below ridgecrests, behind terrain breaks, and in gullies. Fresh wind slabs are expected to be 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
    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.

Confidence

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

Weather Forecast

Friday: Light flurries with strong westerly winds and freezing levels near valley bottoms. Saturday: Light to moderate snow with 10-20cm possible by the end of the day. Continued strong westerly winds and freezing levels rising throughout the day to 1800m by the evening. Sunday: Continued light flurries or rain at lower elevations with freezing levels as high as 2000m.

Avalanche Summary

Recent explosive control throughout the region produced results up to Size 2.5 on the mid-February persistent weakness. The 20-50cm slabs were very touchy with some wide propagations.

Snowpack Summary

A cohesive slab continues to settle over the mid-February surface hoar, which is generally down in the 40-55cm range. Recent reports include whumpfing and cracking, and moderate but sudden compression 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. Basal facets have only been reactive on steep, shallow, and rocky slopes, but operators continue to monitor this layer in tests. Triggering this deep persistent weak layer is unlikely, but shallow snowpack areas or shallow weak areas adjacent to deeper wind loaded slopes are the most suspect locations.

Régions couvertes