Bulletin d’avalanche

Banff Yoho Kootenay

Apr 17 – 18, 2015Parks Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Sun
Mon
Alpin
Sans niveau
Limite forestière
Sans niveau
Sous la limite
Sans niveau
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Points saillants

We are gradually moving into true spring melt- freeze conditions although higher N facing terrain still has a winter snowpack. Start early, minimize exposure to steep solar aspects later in the afternoon, and enjoy the fast travel.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1–2
    Wind slabs are becoming less reactive, but watch for how these are bonding to the harder surfaces below especially on high N aspects.

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    Many large cornices have formed recently, and there have been numerous reports of cornice failures over the last week. In isolated events these have been big enough to trigger the deep basal facets.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    Expect an increase in solar triggered avalanche activity with daytime heating over the weekend. It is possible that wet slides could trigger the basal facet layers if they have enough mass. Start early and be off steep solar aspects by midday.

Weather Forecast

Winds are forecast to switch to the North and calm down on Friday night as a ridge of high pressure begins to build. No new precipitation is expected on Saturday or Sunday. Freezing levels should start at valley bottom overnight but rise to 2200m on Saturday and 2300m on Sunday. Early starts and finishes will be important.

Snowpack Summary

Moist snow up to 2100m on all aspects and to ridge top on all solar aspects. Lots of wind effect in alpine areas. Recent wind slabs are beginning to bond but may still be an issue at higher elevations. Cornices are a major concern with the winds and warm temperatures. Recent cornice failures have triggered the basal facets in several locations.

Avalanche Summary

Wet loose natural avalanches up to size 2 were seen Friday afternoon with the warm temperatures. Isolated whumpfing was still noted in the Observation Sub Peak area Thursday and was likely due to new wind slabs sitting over sun crust. On Wednesday, a large cornice release triggered a size 3 avalanche on the basal facets in the Sunshine backcountry.

Confidence

Régions couvertes