Bulletin d’avalanche

Northwest Coastal

Dec 30 – 31, 2012Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

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

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Potential new windslab and older buried wind slabs lie in the alpine and at treeline. Older windslabs have mostly been formed by the NE flow whereas the new windslabs will come with South winds.

  • Loose Dry

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Loose dry avalanches will be easily triggered on steep terrain and in sheltered areas.

Confidence

Good

Weather Forecast

Sunday night and Monday: The weakening front should reach the region during the night giving light to moderate precipitations through the day and moderate winds from the South. Freezing levels should stay near valley bottom. Tuesday: The ridge of high pressure rebuilds to give place to clearer skies but similar moderate winds from the South. Temperatures are expected to warm up slightly reaching -5 C in the alpine. Cloud cover should increase as the day goes as another frontal system approaches. Wednesday: The Northern part of the region could receive considerable amounts of precipitation with the system and high winds while the Southern part of the region looks much dryer for the moment.

Avalanche Summary

A couple natural slab avalanches were observed up to size 2.5 that would have been occurred on steep lee features in the Bear pass area.

Snowpack Summary

New wind slabs will most likely take form on lee side of ridges in the alpine and at treeline during the day tomorrow. These will be touchy until they have time to bond to the old surface, which could take a couple days. In sheltered areas, the new snow could hide older windslabs that were formed by the previous NE winds. The mid-pack is generally well settled. Note that a layer of surface hoar buried in the upper meter of the pack has been observed in the Shames backcountry.  In sheltered areas and below treeline, 40 cm of low density snow overlies a stiffer base. Near the base of the snowpack, a crust/facet layer continues to give hard, sudden results to no 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.

Régions couvertes