Bulletin d’avalanche

Banff Yoho Kootenay

Feb 8 – 9, 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
4 · Fort
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Points saillants

Yet another storm system will continue to overload the highly sensitive snowpack. Avoid all avalanche terrain. This includes the runout zones of any avalanche path as we have seen avalanches run to valley bottom.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - 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. The recent and forecasted snow will continue to overload these layers.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1–2.5
    Look for storm slab formation with warmer temps and forecasted snow amounts. Winds will be variable in direction through the storm period which may result in widespread slab distribution. These new slabs may also be sitting on previous wind slabs.

Weather Forecast

Another storm should track through our region starting Wed night and will continue into Thursday. With this we can expect up to 20-30cm along the divide, strong W winds, and warming alpine temperatures (-5C ).  As the storm ends tomorrow, winds will shift to the East and diminish with a cooling trend.

Snowpack Summary

Storms from the last 7 days have deposited up to 70cm of snow. The main concern continues to be the 3 persistent weak layers of surface hoar and/or facets that are found between 50 and 150cm down in the snowpack. We continue to observe sudden test results, whumphing and large propagations on these layers.

Avalanche Summary

There have been large avalanches every day this week, mainly to size 3 with some larger. Most of these avalanches have been failing on the persistent layers mentioned above, with the odd avalanche going on the ground. Many close calls have been associated with these events.

Confidence

Régions couvertes