Bulletin d’avalanche

Banff Yoho Kootenay

Feb 1 – 2, 2018Parks Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

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

More avalanche control today resulted in many large avalanches, some running to the end of their runouts. Now is a good time to stay out of avalanche terrain!

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–2.5
    Recent winds and new snow have formed slabs in leeward areas of alpine and treeline terrain, and caused natural avalanches. The slabs are plump and ripe for triggering, and will likely step down to persistent weak layers.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    2–3.5
    There are three weak layers in the upper snowpack: Jan 16, Jan 6, and Dec 15. All are a mix of sun crust, surface hoar and facets depending on your aspect and elevation. Avalanches are occurring on these layers and human triggering is almost certain.

Weather Forecast

Continued light precip and winds on Thursday until the next storm arrives on Friday/ Saturday. Temperatures look to remain cool throughout. Precip amounts are greatest on the west of the divide but range from 20-40 cm over the next 3 days. Winds will increase to strong from the west on Friday.

Snowpack Summary

40-80 cm of snow over the last seven days has overloaded 3 persistent weak layers of surface hoar and facets in the upper half of the snowpack: Jan 16 down 30-50cm; Jan 6 down 40-70cm; and Dec15 down 50-100cm. A major avalanche cycle is ongoing with avalanches running fall path on these layers and some stepping down even deeper.

Avalanche Summary

Natural activity has tapered slightly, but big results with explosives proves that these layers are prime for triggering. Results up to size 3.5 again today with deep fractures and wide propagations. Avalanches were triggered by 95% or more of the shots. Some avalanches ran full path and put dust or debris on roads

Confidence

Due to the number of field observations

Régions couvertes