Bulletin d’avalanche

Purcells

Dec 7 – 8, 2013Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Mon
Tue
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
    Taille
    1–3
    Recently, strong winds from the North have redistributed storm snow, forming wind slabs in exposed lee terrain. Wind slabs found on these aspects are not typical, and they may surprise you.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–5
    In deeper snow areas, it may be possible to trigger an avalanche on a layer of buried surface hoar. In shallower ones, watch for a weak sugary facet layer near the base of the snowpack.

Weather Forecast

The dominating arctic ridge continues, bringing cold and dry conditions through the forecast period.Sunday: Mainly sunny with cloudy periods. Alpine temperatures are showing a high of -20. Light ridgetop winds from the NW.Monday: Mix of sun and cloud. Alpine temperatures are showing a high of -15. Ridgetop winds strong from the West. Tuesday: A mix of sun and cloud. Alpine temperatures are showing a balmy -13. Ridgetop winds are light from the East.

Avalanche Summary

No recent avalanche activity to report.

Confidence

Poor - Due to the number of field observations

Snowpack Summary

Snowpack depths at treeline vary across the region, averaging 70-110 cm. In the Southern part of the region there is 40-70cm of new snow over the late-November surface hoar/ crust/ facet interface that may be reactive, especially in sheltered northerly aspects where the surface hoar is better preserved.In the northern part of the region the lower/mid snowpack is fundamentally weak, composed of an early season crust (more prevalent on north aspects) and weak faceted crystals above and below the crust. This may be reactive from thin spot triggers, or larger triggers (sledder getting air time and dropping onto the suspect slope below). Strong NE winds after the storm have caused reverse loading and wind slab formation on SE through W aspects on open slopes and behind terrain features.While many areas did not receive enough new snow to create a new slab problem on top of these weak layers, there are likely areas where a persistent slab does exist.

Régions couvertes