Bulletin d’avalanche

South Rockies

Mar 3 – 4, 2013Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Tue
Wed
Alpin
4 · Fort
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Large cornices have formed with recent snow and wind. They may be weak and fail, especially if the sun comes out. Cornice fall in itself is dangerous, plus it could trigger slab avalanches on slopes below.

  • Loose Dry

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–3
    Loose dry avalanches may occur, especially from steeper terrain features and slopes that have seen  little wind effect.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–5
    Significant storm slabs have built, especially at upper elevations. They may be particularly touchy on slopes lee of the wind and are likely triggered by the weight of a person. If the sun shines through, natural avalanche activity may spike.

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

The pattern turns cooler, with some sunny skies. The next low pressure system will begin to effect the region on Tuesday, bringing cloud cover and new snow.Monday: The ridge will move over all regions and dominate the weather pattern. Lingering cloud until mid-day with possible sunny skies in the afternoon. Ridgetop winds light from the South.  Alpine temperatures near -7 and freezing levels around 1200 m in the afternoon. Tuesday: The low will bring a milder southerly flow over the region and push a weak and poorly timed upper wave across the Kootenay, Columbias and South Rockies. Alpine temperatures -7 and freezing levels 1400 m. Ridgetop winds moderate from the SW. Wednesday: Moderate snow amounts with ridgetop winds light from the SW. Alpine temperatures near -6 and freezing levels 1600 m falling to valley bottom overnight.

Avalanche Summary

On Saturday a widespread natural avalanche cycle occurred. Most of the avalanches were size 1.5-2 with a few isolated size 2.5. Natural cornice fall occurred triggering slabs on the slopes below. At lower elevations loose wet avalanche activity occurred up to size 1.5.

Snowpack Summary

Up to 40 cm of storm snow has fallen. Storm slabs have been reactive naturally, especially on slopes lee to the wind. The new snow has been transported onto lee slopes by strong west and southwest winds creating wind slabs. Cornices have grown large on ridgelines and may become weak, especially if the sun shines through. In areas unaffected by the wind, loose dry sluffs are likely.Mid and lower snowpack layers are generally well settled.

Régions couvertes