Bulletin d’avalanche

South Rockies

Feb 1 – 2, 2019Avalanche Canada
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Archivé · expiré 8 years ago

Danger d’avalanche

Sun
Mon
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
4 · Fort
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Points saillants

Precipitation amounts overnight Friday are higher than what was forecast with some areas  in the region (particularly along the divide) receiving 30cm + snow. In light of this avalanche danger is RATED as high. Updated Feb 2, 2019.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–1.5
    Some new snow combined with moderate to strong southwest winds will have created wind slabs in the lee of terrain features at upper elevations.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5
    Around 20 to 40 cm of snow sits above a weak layer of feathery surface hoar crystals, which is best preserved in shaded and sheltered areas between 1500 m and 1900 m. On southerly aspects, the snow sits on a hard melt-freeze crust.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–3
    The bottom of the snowpack consists of weak and sugary faceted snow. There is a relatively low likelihood of triggering this layer at the moment, but the consequences remain high, as avalanches on this layer will be large and destructive.

Confidence

Moderate -

Weather Forecast

FRIDAY Night: Cloudy with light snowfall, accumulation 5-30 cm, moderate to strong southwest winds, alpine temperature -5 C, freezing level 1400 m.SATURDAY: Cloudy with flurries, accumulation 5 cm, light to moderate southwest winds, alpine temperature -5 C, freezing level 1300 m.SUNDAY: Cloudy with isolated flurries, light east winds, alpine temperature -24 C.MONDAY: Mix of sun and cloud, light east wind, alpine temperature -20.

Avalanche Summary

The likelihood of triggering avalanches will increase with new snow and wind. On Wednesday, a skier triggered a small slab at treeline on a west to northwesterly aspect. On Tuesday, a small avalanche triggered by a snowmobile was observed, releasing on the surface hoar layer described in the Snowpack Summary. Shooting cracks were also observed, suggesting instability with that layer.

Snowpack Summary

New snow Friday evening will continue to build a slab over a weak layer of feathery surface hoar crystals, which is suspected to buried about 10 to 30 cm. The surface hoar is most prominent between 1500 and 1900 m but has been found up to 2100 m. On south aspects, the snow overlies a melt-freeze crust to the top of the mountains.The middle of the snowpack is generally consolidated. The bottom half of the snowpack is unconsolidated and composed of weak and sugary faceted grains.

Régions couvertes