Bulletin d’avalanche

Waterton Lakes

Dec 24 – 27, 2016Parks Canada
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Archivé · expiré 10 years ago

Danger d’avalanche

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

Cooling temperatures will exert a slow stabilizing influence on the snowpack.  For Saturday, human triggering of Large avalanches remains Likely in specific areas. Be especially cautious in areas of variable snowpack depth.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    These are more widespread than usual, existing on most aspects and elevations due to the intensity of previous winds. They will be hard to spot under new snowfall. New Wind Slabs will build with forecast Strong Westerlies on Monday.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–3
    Nearby operations have reported these failing in the middle of the snowpack, and in some cases stepping down to ground. They are most likely to be triggered in thin Rocky areas, which are more widespread in the Eastern areas of the Park.

Weather Forecast

Saturday: An Upslope flow brings light snowfall and light - moderate Easterly winds. Temperatures fall, from -10 to -15.Sunday: A building ridge causes flurries to taper off, with some afternoon sun possible. -15, light winds.Monday: Return of the Westerlies! Expect: racing clouds, Strong Westerly winds, blowing snow, and rising temperatures.

Snowpack Summary

New snowfall is burying several layers of Hard Wind Slab at all elevations, formed by previous Extreme Westerly winds. In deeper snowpack areas, the Wind Slabs are sitting on a midpack of small facets, which have produced shears in tests. In thin snowpack areas, they are sitting on weak, large, developing Depth Hoar, producing Sudden shears.

Avalanche Summary

Explosives control work at neighboring avalanche operations have been producing Large avalanches daily in Wind exposed terrain, especially in areas that were shallow prior to recent wind loading from the West.Shooting cracks and Whoomphing were observed in pockets of Hard Wind Slab over Depth Hoar in Eastern (shallow snowpack) areas on Friday.

Confidence

Due to the number and quality of field observations

Régions couvertes