Bulletin d’avalanche

Banff Yoho Kootenay

Dec 19 – 20, 2019Parks Canada
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Archivé · expiré 7 years ago

Danger d’avalanche

Fri
Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Recent SW winds have stripped the alpine, and loaded lee features with wind slabs.  Good skiing can be found in sheltered areas. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2

    48 hrs of moderate to strong  winds have formed new wind slabs at alpine and tree line elevations. The distribution of the new load is uncertain. Where it is present you can expect the new load to be reactive in the short term.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–3

    The recent snow sits over weak facet and crust layers. As time goes on the chance of triggering is becoming less likely, but there is lots of uncertainty as to where you could trigger an avalanche and what it will take to get it moving.

Weather Forecast

Thursday - expect light flurries, moderate SW wind, and mild temperatures in the -5 to -10 range

Friday - the next storm begins elevating the avalanche hazard as it brings warmer temps (freezing levels at 1600 m), strong SW wind, and snow (15-30 cm depending on the weather model)

Saturday -  expect another 10-15 cm

Snowpack Summary

Strong winds have formed new wind slabs at alpine and tree line. The distribution of this new load is uncertain. Beneath the recent 40-60 cm of storm snow, the snowpack structure is generally weak, consisting of facets and depth hoar. The Nov crust is present up to 2500m and ~30 cm up from ground. Snowpack depths at treeline range from 80-160 cm.

Avalanche Summary

On Tuesday there was a Skier involvement in a size 2 windslab avalanche triggered on a convex roll at treeline (Paget Peak) and a natural size 2 windslab on a S alpine aspect of Noseum Peak.  Local ski hills continue to report small wind slabs reactive to ski cuts, although slightly less reactive compared to Tuesday

Confidence

Intensity of incoming weather systems is uncertain on Friday

Régions couvertes