Bulletin d’avalanche

Purcells

Nov 27 – 28, 2024Avalanche Canada
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Archivé · expiré 2 years ago

Danger d’avalanche

Fri
Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Fresh and reactive wind slabs may form at treeline and above as westerly winds increase on Wednesday.

Start conservative and watch for signs of instability like cracking or whumpfing.

Problèmes avalancheux

  • Wind Slabs

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

    Fresh and reactive wind slabs could form on Wednesday. Especially at ridgeline and in exposed terrain features.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2.5

    Deep persistent slab avalanches have recently failed on weak faceted snow at the base of the snowpack. This problem is most likely found in the alpine and at treeline on smooth slopes.

Confidence

Low

Avalanche Summary

On Monday, one small (size 1) rider triggered persistent slab avalanche was reported. This occurred below treeline.

Last weekend, numerous natural and human-triggered persistent slab avalanches (up to size 2.5) were observed near Invermere. These primarily occurred on north through southeast aspects at treeline and above.

Smaller wind slab avalanches could step-down to the basal facets, initiating a larger slab avalanche.

If you head out please submit a MIN.

Snowpack Summary

10 to 15 cm of new snow fell over the weekend. In wind-exposed areas cracking and whumping have been reported.

Down 40 to 50 cm sits a layer of surface hoar primarily found on shaded slopes, or on a thin crust on sunny slopes.

A crust exists near the bottom of the snowpack. This crust may have weak, sugary facets on top.

Snowpack depths are reported to be 50-70 cm at treeline elevation.

Weather Summary

Tuesday Night

Cloudy with clear periods. 15 to 25 km/h northwest ridgetop wind. Treeline temperature -10 °C.

Wednesday

A mix of sun and cloud. 15 to 35 km/h northwest ridgetop wind. Treeline temperature -8 °C.

Thursday

A mix of sun and cloud. 10 to 20 km/h west ridgetop wind. Treeline temperature -8 °C.

Friday

A mix of sun and cloud with isolated flurries. 15 to 50 km/h west ridgetop wind. Treeline temperature -12 °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.
  • Be careful with wind-loaded pockets, especially near ridge crests and rollovers.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

Régions couvertes