Bulletin d’avalanche

Purcells

Mar 21 – 22, 2012Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

Be wary of any slopes receiving direct sun. Solar warming could trigger avalanches or weaken existing slabs.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Wind slabs can be found in the alpine and at treeline, behind ridges and terrain breaks. Large cornices are also looming and could trigger deep weak layers on the slope below.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    4–8
    Avalanches failing on a persistent weak layer are deep and destructive. Choose conservative terrain, as the consequences of triggering this layer could be huge.

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Thursday: Light snow. 5-10cm. Light to moderate south-west winds. Freezing level valley floor.Friday/Saturday: Clear and sunny. Light winds. Afternoon temperatures rising on sunny slopes, with the freezing level falling to valley floor at night.

Avalanche Summary

In the Dogtooth Range on Tuesday, a size 3 slab was triggered by a skier on a north aspect. It's suspected to have initiated on the February weakness, and stepped to ground. Two large slabs (size 2-2.5) also released naturally on north to north-east aspects, up to 1 m deep. There were two snowmobile-triggered size 3 avalanches in the southern Purcells near Kimberley (read more in 'related incidents'on this page). I'm concerned about strong solar warming on Friday and Saturday potentially triggering cornice fall or surface avalanches, which could step down to persistent weaknesses and create very large avalanches.

Snowpack Summary

Newly formed soft wind slabs were touchy on Wednesday in specific terrain. Deeper in the snowpack, the major concerns are the mid-February persistent weak layer, buried 1-2 m deep, and facets at the base of the snowpack. Neither of these has truly healed and sporadic very large avalanches continue to occur.

Régions couvertes