Bulletin d’avalanche

Northwest Coastal

Dec 24 – 25, 2012Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Wed
Thu
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    New wind slabs have formed in response to down-valley winds. These could be triggered by the weight of a person or snowmobile.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1–7
    A deeply buried weakness may be triggered from thin, rocky snowpack areas or with a large trigger.

Confidence

Fair

Weather Forecast

Tuesday: Moderate SE winds. Alpine temp -14. No precipitation.Wednesday: Light SE winds. Alpine temp -8. No precipitation.Thursday: Light S winds. Alpine temp -8. Light to moderate snow.

Avalanche Summary

On Saturday, several natural size 1-2 loose dry and thin slab avalanches failed in steep isolated terrain features wind-loaded by outflow (down-valley) winds. Explosives triggered size 2-3 slabs which failed near the ground in facets. Near Bear Pass, natural ice fall triggered size 2.5 and 3 loose snow avalanches, entraining old storm snow. No avalanches were reported on Sunday.

Snowpack Summary

Wind slabs and cornices have developed on a fairly widespread basis and may be found on many slopes due to variable wind directions. Surface faceting is likely to continue while the weather remains cold. A layer of surface hoar buried in the upper metre of the pack has been observed in the Shames backcountry. The mid-pack is generally well settled. Near the base of the snowpack, a crust/facet layer continues to give hard, sudden results in snowpack tests. This weakness is unlikely to be triggered by a single person, but it remains possible with a very heavy load (e.g. cornice fall) or from a thin-spot trigger point.

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