Bulletin d’avalanche

South Rockies

Mar 16 – 17, 2013Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Mon
Tue
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–4
    Cornices can act as a trigger for avalanches on slopes below.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–6
    New storm slabs may develop with forecast snow and wind, which may bond poorly to a smooth sliding surface.

Confidence

Fair - Forecast snowfall amounts are uncertain on Sunday

Weather Forecast

Saturday night: Light snow. Moderate to strong W winds. Freezing level at valley floor.Sunday: Moderate snow (amounts uncertain). Moderate to strong NW winds. Alpine temperature near -7.Monday: Light snow. Light SW winds. Alpine temperature near -8.Tuesday: Light snow. Light SW winds. Alpine temperature near -7.

Avalanche Summary

A widespread natural avalanche cycle occurred during the last storm in response to heavy rain and/or snow and wind loading. Many were loose wet avalanches in the size 1-2.5 range, which entrained loose moist snow as they traveled. Some size 3 avalanches were reported to have failed at ground in the SE corner of the region. Several wind slabs and cornice-triggered storm/wind slabs were also observed (photos here). By Friday, natural activity started to slow down.

Snowpack Summary

The recent warm storm dropped 10-30 cm of dense snow above about 2000 m and soaked the snowpack with rain at lower elevations.  At high elevations, snow has been transported by strong SW and W winds, creating wind slabs. Cornices are large and fragile in some areas. The new snow was not bonding well to underlying surfaces during the storm. With cooling temperatures, the snowpack should start to stabilize and form a hard surface crust, which new snow may not bond well to. The midpack is generally well-settled. 

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