Bulletin d’avalanche

South Rockies

Feb 11 – 12, 2015Avalanche Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Recent snowpack observations have been extremely limited, and the snowpack will likely need more time to adjust to the recent heavy precipitation.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Warm temperatures could make large cornices overhanging the leeward side of ridgecrests unstable. Not only are they a hazard in themselves, but they could also act as a heavy trigger for large slab avalanches on the slope below.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–4
    Deep unstable storm slabs may linger at higher elevations. As you head into the alpine in search of drier snow, be wary of steeper slopes that haven't avalanched as very large avalanches are a concern.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–5
    A deeply buried week layer which formed in December should still be treated with suspicion. Although not much is known about the current reactivity of this potentially destructive layer, I'd use extra caution in steep, unsupported alpine terrain.

Confidence

Fair - Due to the number of field observations

Weather Forecast

Warm and dry for the forecast period. Freezing levels could rise above 3000 m on Friday, before dropping back down on Saturday. Expect brief periods of solar radiation interspersed with cloudy conditions.

Avalanche Summary

Observations have been essentially non-existent in recent days. This likely speaks more to a lack of observers rather than actual conditions. I'm confident recent storm loading has produced large storm slab avalanches at higher elevations, while loose wet or wet slab avalanche activity occurred at lower elevations where rain fell.

Snowpack Summary

The rain line during recent heavy precipitation generally hovered around 1700m, although there were periods where rain fell into the alpine. Above that elevation, heavy accumulations of moist, dense snow have been pushed by strong southwest winds into much deeper deposits on the lee side of ridgecrests and terrain breaks. This recent storm snow overlies a hard crust, which may have overlying surface hoar that was buried late January. The mid-December crust/facet/surface hoar weakness may be persisting in the mid to lower snowpack at higher elevations.

Régions couvertes