Bulletin d’avalanche

Purcells

Jan 22 – 23, 2024Avalanche Canada
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Archivé · expiré 3 years ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

Fresh wind slabs at higher elevations can be found on all aspects. Expect as temperatures continue to be warm, that human triggered avalanches will be likely.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Wind slabs may be more reactive where they sit on a weak layer of facets.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1.5–3.5

    There is a weak layer of facets and depth hoar near the base of the snowpack in most alpine areas. The likelihood of triggering a deep persistent slab is low, however the consequence of doing so is high.

Confidence

Moderate

Avalanche Summary

On Saturday one large (size 2) avalanche was initiated utilizing explosives. On Friday explosive testing and control work continued and produced many large to very large avalanches. These avalanches where both wind slab and a very large a deep persistent avalanche. On Thursday explosive avalanche control missions triggered a very large avalanche size 3.5. This avalanche failed on the deep persistent slab layer.

Snowpack Summary

Up to 40 cm of low density new snow combined with southerly winds has developed new and reactive wind slabs. In areas protected from the wind, expected slab development as settlement of the new snow due to warming continues. Below, weak faceted snow can be found in many areas that are protected from the wind.

The mid and lower snowpack is generally weak with several layers of note. Of greatest concern is a well preserved layer of weak facets and/or depth hoar located at the bottom of the snowpack, particularly in alpine terrain.

Snowpack depths at treeline range from 70 to 160 cm.

Weather Summary

Sunday Night

Mainly cloudy with flurries, 1-2 cm of snow, southwest ridgetop wind 10 to 20 km/h, treeline temperature -9 °C.

Monday

Mainly cloudy with isolated flurries, 1-2 cm of snow, southwest ridgetop wind 10 to 20 km/h, treeline temperature -3 °C.

Tuesday

Mainly cloudy with isolated flurries, 1-2 cm of snow, southwest ridgetop wind 10 to 30 km/h, treeline temperature -2 °C.

Wednesday

Mainly cloudy with isolated flurries, 1-2 cm of snow, southwest ridgetop wind 10 to 20 km/h, treeline temperature -4 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.

Régions couvertes