Bulletin d’avalanche

South Rockies

Jan 3 – 4, 2012Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Thu
Fri
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Wind slabs can be found on North through Southeast aspects. Cross-loading is possible on open slopes oriented parallel to the wind. You may find wind slabs further down the slope or on open wind exposed areas below treeline.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    3–6
    Warm temperatures may consolidate the snow above the surface hoar into a slab that may propagate wide avalanches. This mid-December surface hoar/ facet layer is found mainly in the Western parts of the region.

Confidence

Good - -1

Weather Forecast

Wednesday: Mix of sun and cloud. Light precipitator today up to 5mm. Ridgetop winds from the SW 70-100km/hr. Freezing levels rising to 2000m throughout the day. Thursday: Snow amounts up to 5cms in the morning. Ridgetop winds from the West 55-70km/hr. Freezing levels falling back to valley bottom midday. Friday: Mix of sun and cloud. Freezing levels remain near valley bottom. Ridgetop winds light-moderate from the SW.

Avalanche Summary

On Monday a skier triggered a size 2 slab avalanche in the Harvey Pass area. A wind slab from the ridgecrest was triggered, then stepped down 55cms to a weak surface hoar/ facet layer beneath the surface. Please visit our incident report database on our website for more details @ avalanche.ca.

Snowpack Summary

The CAC Field team headed to Harvey Pass on Tuesday and completed a fracture line profile on yesterday's skier triggered avalanche. The total HS (height of snow) in that area is 180cms. A stiff wind slab was triggered and stepped down 55cms to the mid-December surface hoar/facet layer. Compression tests done showed hard results, but sudden planar characteristics. I suspect you can find this buried layer to the West of the divide in most locations. As soon as you travel to the east surface hoar is spotty, and/or non-existent. The snowpack to the east is 100-120cms in depth, and widespread wind slabs have formed lee to the SW in upper elevations. Many windward areas are scoured. The mid pack is generally well consolidated. At the bottom of the snowpack 20cms of 4F facets and depth hoar exist.

Régions couvertes