Bulletin d’avalanche

Cariboos

Feb 28 – Mar 1, 2013Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Sat
Sun
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
4 · Fort
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Points saillants

Very dangerous avalanche conditions exist in the backcountry. Avoid all avalanche terrain!

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    3–7
    Additional loading from snow and wind, or the weight of a rider could be enough to trigger the February 12 persistent weak layer.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    3–7
    Expect natural avalanches to run during periods of rapid loading by new snow and wind. Due to the presence of a deeply buried weak layer, the potential size of avalanches could be very large.

Avalanche Summary

On Tuesday, a cornice fall triggered a size 3.5 avalanche on a northeast aspect, which ran for 800 m. Other natural and explosice-triggered avalanches were observed up to size 3 on a range of aspects. On Wednesday, a few size 2 natural avalanches were observed in steep terrain.

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

Synopsis: Starting Thursday night, a Pineapple Express will bring moisture to this region through the forecast period. Due to the narrow moisture stream, some areas may see more or less than the stated amounts below.Thursday night. 10-15 cm new snow, with the possibility of local enhancement. Very strong SW winds.Friday: Heavy snow/rain, up to 30 cm/mm. Even higher accumulations possible in western upslope areas. Freezing level around 1600 m. Southwesterly ridgetop winds to 70 km/h.Saturday: Moderate snow/rain (around 10 cm/mm), higher amounts possible. Freezing level around 1600 m. Southerly winds around 30 km/h.Sunday: Moderate to heavy snow (15-20 cm). Freezing level around 1500 m. Light winds.

Snowpack Summary

40-70 cm of recent storm snow forms the upper layer of the snowpack. Strong southwest winds have redistributed the new snow into deep wind slabs on exposed lee slopes and cross-loaded gully features. The February 12 persistent weak layer (crust, and/or surface hoar) is now down 60-80 cm. It is primed for triggering and has been reacting readily to both natural and human triggers on all aspects and a wide range of elevations. The effect of a large storm on the snowpack, particularly one accompanied by warm temperatures, wind and possibly rain, will be dramatic. Deeper persistent weak layers from early February and late January continue to show planar failures when moderate to hard forces are applied in snow pack tests. These deeper layers have not been reactive to the weight of a rider, but they could potentially be triggered during the upcoming storm, further increasing the potential size of avalanche events.

Régions couvertes