Bulletin d’avalanche

South Rockies

Jan 4, 2019Avalanche Canada
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Archivé · expiré 8 years ago

Danger d’avalanche

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

The storm is loading a weak snowpack. Travel in avalanche terrain is not recommended.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1–2
    Touchy wind slabs have likely formed with the new snow and strong southwest winds. In sheltered areas, the snowfall may accumulate and form storm slabs.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    2–3
    A substantial amount of snowfall is loading a weak layer of sugary faceted snow. Avalanches triggered on this layer will likely scour to the ground, resulting in large avalanches that can run full-path.

Confidence

High -

Weather Forecast

THURSDAY NIGHT: Cloudy with snowfall, accumulation 10 to 20 cm, moderate to strong southwest winds, freezing level 1500 m.FRIDAY: Cloudy with snowfall, accumulation 5 to 10 cm, moderate to strong southwest winds, alpine temperature -5 C, freezing level 1400 m.SATURDAY: Mix of sun and cloud, light to moderate southwest wind, alpine temperature -5 C, freezing level 1000 m.SUNDAY: Cloudy with light snowfall, accumulation 5 to 10 cm, light to moderate southwest winds, alpine temperature -5 C, freezing level 1000 m.

Avalanche Summary

A natural avalanche cycle may be starting in the region with the substantial amount of recent snowfall. On Wednesday, a naturally-triggered large (size 3) avalanche was observed near Elkford, which likely released on Tuesday. See here. It ran full-path to valley bottom. In the far west of the region, the snowpack has been observed to be weak and touchy, as described here. New snow is loading this weak and touchy snowpack and increasing the likelihood of avalanche activity.

Snowpack Summary

Large variability in snow depths still exists in the region, ranging from practically no snow to almost 200 cm. Upwards of 30 cm of snow fell on Thursday and more is expected on Thursday night into Friday. The snow fell with strong southwest winds, moving the snow around in exposed areas. Expect the deepest deposits in lee terrain features. This snow will sit on previous hard wind slabs, a scoured and shallow snowpack on exposed southerly ridges, and soft snow in sheltered areas.A persistent weak layer of weak and sugary faceted snow that formed during dry and cold weather in early December is buried around 60 to 90 cm. This layer is most likely to be triggered on steep features where snowpack depths are variable.The lower snowpack has a weak structure composed primarily of sugary faceted snow around a crust near the ground. Should a shallower avalanche be triggered, it is likely that it would step down and scour to the ground.

Régions couvertes