Bulletin d’avalanche

Banff Yoho Kootenay

Dec 26 – 27, 2013Parks Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Thu
Fri
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

The basal depth hoar can be heard jing, jing, jingling in your snow pit. Conservative terrain choices are important to stay safe when dealing with this overall weak snowpack. Happy holidays. SH

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    Windslabs are prevalent in many areas at upper elevations, and any new snow and wind will contribute to their formation.  Once triggered in steeper terrain, these have been seen to trigger deeper releases on the basal weakness.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–3
    Full depth, human triggered avalanches are likely in specific features. This basal crust/depth hoar problem will last for a while to come.

Weather Forecast

The very windy alpine conditions will continue Thurs and Fri. with strong to extreme westerlies. Light snow amounts of 5-10cm expected over the next 2 days and freezing levels to valley bottom.

Snowpack Summary

5-10cm of new snow in the W tapers to nothing in the E. A variety of surface weaknesses including widespread windslabs in the ALP and isolated surface hoar at TL & BTL sit on a generally weak snowpack. The real concern is the facet/depth hoar/crust combo at the base of the snowpack which been triggered by light loads recently and can't be trusted.

Avalanche Summary

A size 2.5 was observed 2 days ago on a N aspect of Mt. Fairview. It was initiated as a wind-induced spindrift avalanche which pulled out a slab that failed near the ground. This is indicative of the widespread basal weakness present in the snowpack.

Confidence

Due to the quality of field observations on Wednesday

Régions couvertes