Bulletin d’avalanche

South Columbia

Feb 22 – 23, 2013Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Sun
Mon
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
3 · Marqué
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Points saillants

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–6
    Storm loading has added additional stress to a persistent weak layer of surface hoar or a sun crust which now lie up to 80cm below the surface. Triggering this weakness may result in surprisingly large avalanches.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–5
    Friday's wind and significant accumulations have created a potent new storm slab with the potential for large avalanches. Watch for increased reactivity in wind-affected terrain.

Confidence

Fair - Intensity of incoming weather is uncertain for the entire period

Weather Forecast

Saturday: Light to locally moderate snowfall / Moderate northwest winds (with strong gusts) / Freezing level at 700mSunday: Light to locally moderate snowfall / Moderate to strong west winds / Freezing level at 900mMonday: Light snowfall / Light southwest winds / Freezing level at 1000m

Avalanche Summary

Observations from the region have been very limited due to poor visibility; however, there have been reports of widespread avalanche activity occurring within the recent storm snow. I expect widespread avalanche activity to continue throughout the weekend with the potential for very large avalanches.

Snowpack Summary

Moderate to locally heavy snowfall and wind have created potent new storm slabs which are most reactive in wind-exposed terrain. These new accumulations are adding to the 25 to 55cm of snow which overlie the weak surface hoar layer which was buried on February 12th. The additional weight of the new snow and wind affect is expected to add reactivity to this persistent weakness which remains a primary concern for professionals in the region. This interface has also shown reactivity on south aspects where a sun crust also exists. There are older weak layers (surface hoar, crusts on solar aspects, facets) that are now buried down around 60-80 cms and also at about 110 cms. These layers have been unlikely to trigger by skiers, but they may still be sensitive to large loads like avalanches in motion or cornice fall.

Régions couvertes