Bulletin d’avalanche

Banff Yoho Kootenay

Jan 8 – 9, 2015Parks Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

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

Although natural avalanche activity will taper, avalanche control on Jan. 7th produced size 2 (deep enough to bury a human) or greater avalanches on most if not all shots. Now is the time for caution!

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–2
    Warms temperatures and wind on Jan. 7th have created windslabs that overly the Dec. 18th facet/ surface hoar/ crust layer.  Any avalanche triggered on this layer will likely step down to the deep persistent slab layer.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–3
    The lower part of the snowpack is weak and will be overloaded easily with much additional load. Avoid steep (>35 degree) open slopes at treeline and above. Shallow rocky areas are likely areas to trigger this problem.

Weather Forecast

NW flow continues but with a break in the weather systems for Thursday. Expect clearing skies and temperatures falling to between -10 and -15 and falling winds. Friday the temperatures will warm back up again, with the possibility of light precipitation.

Snowpack Summary

Moderate SW winds and warm temperatures today created windslabs at alpine and treeline elevations. These windslabs bond poorly to the Dec 18 layer of facets, crust and some surface hoar down 20-40 cm. At the bottom of the snowpack, the deep peristent basal problem is still a concern and was triggered using explosives today.

Avalanche Summary

Avalanche control in Kootenay and Yoho Park produced between 10-15 avalanches between size 2 and 3. Mostly size 2's with a couple of larger ones. Human triggering is very likely at this time.

Confidence

Due to the number and quality of field observations

Régions couvertes