Bulletin d’avalanche

Kootenay Boundary

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

Danger d’avalanche

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

There is low confidence in the strength of the warm snowpack at all elevations.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–6
    A deeply buried week layer which formed in December should still be treated with suspicion. Although not much is known about the current reactivity of this potentially destructive layer, I'd use extra caution in steep, unsupported alpine terrain.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–5
    Deep unstable storm slabs may linger at higher elevations. As you head into the alpine in search of drier snow, be wary of steeper slopes that haven't avalanched as very large avalanches are a concern.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Pushy loose wet and wet slab avalanches remain a concern at lower elevations where rain has saturated the snowpack. Pay close attention to daytime temperatures, and whether snow surfaces are moist or refrozen.

Confidence

Fair - Due to the number of field observations

Weather Forecast

Warm temperatures with light precipitation possible for the forecast period. Freezing levels could rise above 3000 m on Friday, before dropping back down on Saturday. Alpine winds are expected to me moderate southwesterlies on Thursday and Friday, before picking up and switching to northwesterlies throughout the day on Saturday.

Avalanche Summary

Reports from Tuesday include evidence of old natural slab avalanches up to Size 2.5. Heavy triggers such as explosives and snowcats were able to trigger 20-90 cm deep storm slabs up to Size 2, but no new naturals were observed and ski-cutting was ineffective.

Snowpack Summary

The rain line during recent heavy precipitation generally hovered around 1700m, although there were periods where rain fell into the alpine. Above that elevation, heavy accumulations of moist, dense snow have been pushed by strong southwest winds into cornices and deeper deposits on the lee side of ridgecrests and terrain breaks. Recent storm snow is poorly bonded to a hard crust, which may have overlying surface hoar, that was buried late January. The mid-December crust/facet/surface hoar weakness may be persisting in the mid to lower snowpack at higher elevations.

Régions couvertes