Bulletin d’avalanche

Kootenay Boundary

Jan 7 – 8, 2015Avalanche Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Warm temperatures and sunshine on Thursday should maintain touchy conditions. Conservative terrain selection is still crucial at this time.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–5
    There is potential to trigger avalanches on a weak layer buried 80-100 cm deep. Be vary wary of slopes that did not slide slide during the last storm and be aware of the potential for triggering slabs from a distance.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–4
    Forecast sunshine and mild temperatures could maintain touchy storm slab conditions and trigger loose wet slides on steep sun-exposed slopes.

Confidence

Fair - The weather pattern is stable

Weather Forecast

Synopsis: A strong ridge of high pressure will maintain dry, sunny, and mild conditions for Thursday. An above freezing layer (AFL) is likely between 1500 and 2500 m. Ridge top winds should be light or moderate from the NW. On Friday the AFL should shrink and we might start seeing increasing cloud throughout the day. Theres a chance of flurries on Saturday as the freezing level drops back to valley bottom.

Avalanche Summary

Most areas reported a fairly widespread and large natural avalanche cycle on Tuesday. Many of these slides stepped down to mid-December persistent weak layer and produced avalanches up to Size 3. There were also reports of skiers and machines triggering slab avalanche from a distance (remotely and sympathetically triggered).

Snowpack Summary

30 - 60 cm of snow fell across the region earlier this week with moderate southwest winds shifting these accumulations into deeper deposits in lee terrain. Warm temperatures may keep the storm storm slab sensitive to light triggers. The new snow overlies a variety of old surfaces which include heavily wind-affected surfaces in exposed locations, faceted powder and buried surface hoar in sheltered terrain. Up to 100 cm below the surface, you'll likely find a touchy weak layer of surface hoar sitting on a thick rain crust. This widespread persistent weakness exists at all elevation bands, and continues to be the primary layer of concern for the region. With the recent load of storm snow, I expect this layer to remain active with the potential for large and destructive avalanches. At the base of the snowpack, a crust/facet combo appears to have gone dormant for the time being.

Régions couvertes