Bulletin d’avalanche

South Rockies

Mar 20 – 21, 2014Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

Watch the temperature and solar warming! Heat and cornices are two great ways to shake-up the snowpack over the next couple of days

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Cornices in the region are now very large and fragile. A cornice fall could be destructive by itself, and could trigger a large avalanche on the slope below.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Significant snowfall and steady southwest winds have created a punchy new storm slab which exists at all elevations. Watch for triggering in wind-exposed terrain. If the sun comes out on Friday, the new snow may react as a loose wet avalanche.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–6
    The deep weak layers that formed in early February may be more likely to trigger in the north of the region. Possible triggers at this point include a large cornice fall, a large force in a thin snowpack area or solar warming.

Confidence

Fair - Forecast snowfall amounts are uncertain on Friday

Weather Forecast

Thursday night and Friday: Up to 20cm of snow overnight Thursday, becoming light on Friday / Light to moderate northwest winds / Freezing level at surfaceSaturday: Flurries with a mix of sun and cloud / Light to moderate northwest winds / Freezing level at surfaceSunday: Flurries with a mix of sun and cloud / Light to moderate northwest winds / Freezing level at surface

Avalanche Summary

On Wednesday a size 2 wind slab was accidentally triggered by a skier in the southeast corner of the region. The avalanche occurred on a northeast aspect at about 2600m. Although observations were limited, I expect there would have been a round of storm slab activity in response to new snow and wind on Thursday. Looking forward, continued snowfall will likely promote ongoing storm slab activity while intermittent sunshine may spark a loose wet avalanche cycle.

Snowpack Summary

At the time of publishing this bulletin up to 30cm of new snow had fallen and had been pushed by moderate to strong southwest winds into deeper deposits in exposed lee terrain. Below the new snow is a well settled storm slab which overlies a hard rain crusts. This crust exists on all aspects below 2000m and on solar aspects in the high alpine. North of Sparwood and in the Crow's Nest Pass area the buried crust seems more specific to previously sun-exposed slopes. The deep facet/crust persistent weakness buried at the beginning of February (now down up to 150cm) seems unlikely to trigger in areas where the hard, supportive near-surface crust exists. No matter where you are in the region, this weakness should stay on your radar as any activity at this interface would be large and destructive. Possible triggers include a large cornice fall, a large input in a thin snowpack area or solar warming.Cornices have also become large and unstable.

Régions couvertes