Bulletin d’avalanche

Northwest Coastal

Jan 20 – 21, 2013Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Tue
Wed
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
    Recent extreme westerly winds have redistributed light snow accumulations (heavy in the north) into windslabs in exposed lee and cross-loaded terrain at higher elevations. Although they are gaining strength, human triggering remains possible.

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

The ridge of high pressure will continue to bring dry conditions until Tuesday afternoon at which point the region will see light to moderate snowfall that will continue into Wednesday. Winds are expected to remain generally light from the southwest (moderate in the north). Alpine temperatures are expected to hover around -2.0 on Monday and Tuesday dropping to -5.0 on Wednesday.

Avalanche Summary

Prior to the weekend numerous avalanches ran naturally or with explosives to size 3.5 in the north of the region where recent snow accumulations were the highest. They occurred in response to heavy snowfall and strong to extreme westerly winds. One result pulled down to basal weaknesses that interacted with summer firn. Wind slab and storm slab activity remains a possibility, especially in locations to the north where snow accumulations were greatest.

Snowpack Summary

In areas below treeline that were previously rain soaked a melt freeze crust is now likely to exist. At higher elevations light amounts of recent snow (heavy amounts in the north) were redistributed by strong to extreme westerly winds and now exist as lingering storm slabs and wind slabs..A persistent weakness of surface hoar buried at the end of December sits about 60cm below the surface. It has most likely gained significant strength; however, human triggering may still be possible.The mid and lower snowpack is generally well settled and strong, although well developed basal facets remain a concern in the north of the region.

Régions couvertes