Bulletin d’avalanche

Purcells

Jan 16 – 17, 2013Avalanche Canada
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Archivé · expiré 14 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

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–5
    Wind slabs may be found behind terrain breaks such as ridges and ribs. It may be possible for a wind slab to step down to a deeper instability.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–5
    Persistent weaknesses are variable in their distribution, but can still be triggered by the weight of a person or snowmobile.

Weather Forecast

Thursday: Moderate W winds. Alpine temperature near -4. Freezing level is at valley bottom, with alpine inversions possible (parcels of warm air which could bring relatively warm alpine temperatures). Trace of snow.Friday: Light to moderate W winds. Alpine temperature near -9. No snow.Saturday: Light SW winds. Alpine temperature near -4. No snow.

Avalanche Summary

Several size 1-2.5 wind slabs were triggered naturally and by skiers on Tuesday and Wednesday. Cornice falls were also reported.

Snowpack Summary

Strong NW through SW winds have left wind slabs in many areas, even at treeline. Cornices are unstable in some places. Settled storm snow sits above surface hoar (found especially at and below treeline in sheltered areas), a sun crust (on steep S to SW -facing slopes) and facets. The distribution of these weaknesses is patchy, but where they exist, it may still be possible to trigger a large avalanche with the weight of a person or snowmobile. A strong mid-pack overlies a weak facet/crust layer near the base of the snowpack, which is now considered inactive.

Confidence

Fair - Due to variable snowpack conditions

Régions couvertes