Bulletin d’avalanche

Kootenay Boundary

Jan 12 – 13, 2014Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

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

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–5
    There is a wide spatial variability through the region concerning the persistent weak layers which is creating a complex situation.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Developing windslabs lee of strong W winds and buried windslabs is be the main concern for tomorrow. Beware of the possibility of loose avalanches in steep terrain and of storm instabilities that could linger.

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

Tonight and Monday: Moderate precipitation is expected tonight with extreme W winds. Freezing levels are expected to rise to 100 m on Monday. Tuesday: An upper ridge is building over the region which will give the storm pattern a break. Trace accumulations, a mix of sun and cloud, strong W winds and freezing levels rising to 2000 m. Wednesday: The ridge brings dry, clear and warm temperatures over the Southern part of the province with strong winds from the NW.

Avalanche Summary

There was a natural avalanche cycle yesterday up to size 2.5 from all aspects at all elevations but mostly on N and NE aspects. Some are suspected to have run on the early January surface hoar layer. There was also some small avalanches triggered by skiers without involvement on East aspects.

Snowpack Summary

Accumulations forecasted tonight, strong W winds and rising freezing levels is keeping avalanche conditions dangerous for tomorrow. New windslabs lee of wind will take time to bond to the underlying surfaces, such as older windslabs in the alpine and previous storm snow in sheltered areas. The storm snow is expected to have to potential to sluff in steep sheltered terrain. Under the ~40 cm of recent storm snow, a surface hoar layer is present at treeline and below treeline and is sitting on a sun crust on S facing aspects. Some avalanches are suspected to have stepped down to this layer during the last avalanche cycle. The end of November facet/crust or surface hoar layer down 90 cm (or 50 cm where snowpack is very thin) and the depth hoar or basal facetting are still a concern. The facet/crust layer is most reactive on S and SE aspects slopes in the South-Eastern part of the region and seems to be more problematic on N and NE aspects in the central-Southern part of the region where the surface hoar was preserved.

Régions couvertes