Bulletin d’avalanche

Northwest Coastal

Dec 31, 2011 – Jan 1, 2012Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Mon
Tue
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
3 · Marqué
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Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–5
    Deep wind slabs will continue to develop in exposed lee and cross-loaded terrain in the alpine and at treeline. Large, sensitive cornices are also a current concern above lee slopes.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–6
    There is a possibility of highly destructive avalanches where the deeply buried mid-December crust/facet layer persists. The probability of a deep release may be lower; however, the consequences would be very high.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–5
    Storm slabs could be triggered by the weight of a person or a snowmobile.

Confidence

Fair - Freezing levels are uncertainfor the entire period

Weather Forecast

Heavy precipitation and strong southerly winds are forecast for late sunday and into monday morning. Continued moderate precipitation will follow throughout monday and tuesday with moderate to strong southwest winds.Freezing levels are uncertain for the forecast period; some models showing freezing levels at 650m while other show freezing levels shooting to 1500m. Stay tuned for more info.

Avalanche Summary

Wind slabs and cornice releases dominated recent avalanche observations. Size 2 natural slab activity triggered by cornice fall and numerous skier-triggered size 1 slabs reported in the northern part of the region.Numerous natural size 2 slabs reported in the Skeena area.

Snowpack Summary

A relentless pummelling by snow, strong to extreme winds, and fluctuating freezing levels over the past week has added around 130cm of new snow near Terrace and around 75cm near Stewart. Strong south to southwest winds have created hard and soft wind slabs on lee slopes. Large sensitive cornices also exist.Deeper in the snowpack, buried surface hoar and a crust-facet combo (which extends up to alpine elevations in the south and to 1000m in the north) remain a cause for concern, with the potential for deep, destructive avalanches. Recent observations suggest these layers may be gaining strength; however, I wouldn't write them off just yet.

Régions couvertes