Bulletin d’avalanche

Banff Yoho Kootenay

Feb 9 – 10, 2018Parks Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

Sat
Sun
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
4 · Fort
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Points saillants

http://www.pc.gc.ca/apps/links/goto_e.asp?destination=Avoid all avalanche terrain including crossing runout zones at valley bottom. Natural activity will likely taper over the next couple of days, but human triggering will be as touchy as it gets.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    2–4
    Three weak layers exist in the mid snowpack: Jan 16, Jan 6, and Dec 15. All are a mix of sun crust, surface hoar and facets depending on the aspect and elevation. These layers are very sensitive to triggering both naturally and by human triggering.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1–2.5
    There are storm slabs up to 1m thick on many aspects and elevations from the big storm on Thursday. These will be highly sensitive to triggering and once initiated, can step down to the deeper persistent layers causing very large avalanches.

Weather Forecast

The epic storm has ended and we will see a few "normal" days of weather. -15 to -18C in the alpine Friday with light winds and mainly clear skies and no additional snow.

Snowpack Summary

Thursdays storm dropped 30 - 50cm with variable winds. This combined with other recent snow has overloaded the 3 main mid pack concerns which are the Jan 16th, Jan 6th, and Dec.15 weak layers. These are a mix of facets, crusts and surface hoar and can be found 70cm to over 150cm deep in the snowpack and are currently producing very easy results.

Avalanche Summary

Another widespread cycle Thursday to size 3.5 (what we could see) . These were failing on the above mentioned weak layers. Explosive control was producing size 3 avalanches up to 150cm deep with just the explosive hitting the slope. Most of these avalanches are traveling far into the valley bottom which should be a concern for all users.

Confidence

Régions couvertes