Bulletin d’avalanche

South Coast

Apr 4 – 5, 2014Avalanche Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

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

What's going to happen to the snowpack if it warms up significantly on Sunday/Monday/Tuesday? Read a discussion here...

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    New snow with strong SW winds has set up storm and wind slab problems on steep lee terrain features. Watch for sensitive storm slabs lee of both ridge crest and mid slope features like ribs/rock outcroppings.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–7
    Three buried weak layers exist in the snowpack. Deep releases have become rare, but I would be concerned about an increased likelihood of a large destructive event during a period of intense warming.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Sunday

Weather Forecast

Synopsis: Moderate precipitation expected on Saturday before a ridge of high pressure builds for Sunday and Monday. Saturday: 5-10 cm new snow expected with freezing levels around 1200 m. Winds 40-50 km/h from the SW. Sunday: Scattered showers in the morning, becoming dry in the afternoon with some sunny breaks. Freezing levels around 1200 m. Winds 20-30 km/h from the NW. Monday: Dry. Sunny in the morning, becoming more cloudy in the afternoon. Warm, with freezing levels rising to 2200 m.

Avalanche Summary

Minor sluffing was reported from the Duffey Lake area on Thursday, but no slab avalanche activity was noted. I suspect some relatively small storm slab avalanches occurred Friday in response to the new snow and loading from wind. On Wednesday, a cornice fall on a steep north facing features at 2300m initiated a size 3 avalanche. It likely ran on the early March melt-freeze crust.

Snowpack Summary

5-10 new snow sits above a mix of surface hoar, small grained facets and melt freeze crusts.Recent warm temperatures have helped to settle and strengthen the upper snowpack. Down 30 - 50 cm below the surface, snowpack tests are still producing hard resistant planar shears on the late March crust.The persistent weak layers from early March and early February continue to be a concern. The March melt-freeze crust/surface hoar is reported to be down 60 - 100cm. The February crust/facet/surface hoar layer is now deeply buried down 150 - 250cm.The lower snowpack is strong and well settled.

Régions couvertes