Bulletin d’avalanche

South Columbia

Apr 11 – 12, 2015Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Mon
Tue
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

While it feels like spring in the valley, the alpine has returned to winter. Stay on your toes as a potentially touchy storm/wind slab likely exists at upper elevations.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–5
    Ongoing winds are adding to the already large cornices that loom over many features, possibly increasing the likelihood of failure. A large cornice failure may be able to trigger a slab release on slopes below.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    Snowfall Friday night was accompanied by strong SW winds, and these winds are expected to continue into Sunday. Fresh storm/wind slabs are sitting on crust, facets and/or surface hoar which may keep them touchy into early next week.

Confidence

Fair

Weather Forecast

SUNDAY: Freezing level starting at 1000m, rising to 1600m. Light W/SW winds treeline, Moderate W winds at ridge-crest. Broken cloud cover. No significant precipitation expected.MONDAY: Freezing level rising to 1800m. Light S/SW winds at treeline. Strong SW winds at ridge-crest. Overcast. No significant precipitation expected during the day, 5 to 15cm of snow possible Monday night.TUESDAY: Freezing level around 1500m. Moderate NW winds at all elevations. Scattered cloud cover. Isolated flurries, less than 5cm total snowfall expected.

Avalanche Summary

No new activity to report from Friday. In two separate incidents Thursday cornice fall triggered deep persistent slabs when it impacted slopes below. Both incidents were on north facing alpine features. Loose wet avalanches to size 2 were also observed from south through west facing terrain.

Snowpack Summary

The region picked up around 5 to 20cm of snow Friday night accompanied by strong SW winds burying the old surface which consists of facets, surface hoar and crust. Prior to Friday nights storm the 10 to 45cm that fell the weekend of April 4th remained dry on high elevation polar aspects but had turned moist on east and west facing aspects. South facing features were moving into the spring corn cycle. Down 15 to 65cm you will find the supportive late-March crust that is thought to exist up to around 2100m. Moist snow underneath the late-March crust is ubiquitous in most of the region.Two significant persistent weak layers composed of crust and facets exist in the snowpack. Although they appear to have gone dormant for the time being, we will continue to monitor them closely. Mid-March is down 50 to 100cm below the surface and Mid-February is down 90 to 150cm. Observations indicate that there is significant faceting occurring between the two crusts. While an avalanche failing at either of these interfaces is unlikely, it may be possible on steep unsupported alpine features.

Régions couvertes