Bulletin d’avalanche

South Columbia

Apr 9 – 10, 2013Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Thu
Fri
Alpin
4 · Fort
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Avalanche danger will vary from place to place depending on local snowfall amounts and freezing levels. The heaviest precipitation is expected in the west.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1–5
    New snow and wind will create new storm slabs at high elevations, which may overload a weakness buried in the upper snowpack, creating large avalanches.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Loose wet avalanches and glide slabs may fail naturally in response to rainfall at low elevations.

Weather Forecast

Tuesday night/ Wednesday: 30-50 cm snow. Strong to extreme W winds. Freezing level around 1500 m overnight, rising to about 2000 m in the south (~1700 m in the north) on Wednesday.Thursday: Light snow. Moderate to strong NW winds. Freezing level around 1600 m. Friday: Light snow. Light S winds. Freezing level around 1500 m.

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain for the entire period

Avalanche Summary

Most of the recent avalanche activity has been on high elevation north aspects. A cycle of natural slabs to size 3 which occurred during last weekend’s storm petered to a few size 2s by Monday. A few skier-remote triggered slabs were also reported on Sunday. These either failed on a storm snow weakness, or on surface hoar buried below the storm snow. Below about 2300 m, skiers were triggering loose wet avalanches on steep terrain. Another natural avalanche cycle is expected in response to Wednesday's storm.

Snowpack Summary

40-70 cm recent storm snow is sitting on a variable interface, consisting of a crust, moist snow, surface hoar or facets. The surface hoar or facet interface is mainly found on high-elevation northerly aspects. It has been very touchy, with remote skier-triggering occurring. Forecast precipitation will add to this storm slab problem and create new wind slabs at high elevations, and weaken the snowpack with rain at low elevations. Large cornices are likely to increase in size and become more prone to failure during Wednesday’s storm.

Régions couvertes