Bulletin d’avalanche

East Purcell

Dec 22 – 23, 2025Avalanche Canada
Voir sur la carte
Archivé · expiré 9 months ago

Danger d’avalanche

Wed
Thu
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
Ouvrir la carte complète

Points saillants

Watch for changing conditions as you shift elevation and aspect - wind affected features may remain reactive to human triggers.

Problèmes avalancheux

  • Wind Slabs

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

    Wind affected features may remain reactive to human triggers, especially where they sit over a smooth crust.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–3

    Triggering the surface hoar/facets over the crust is most likely in isolated terrain features above 2100 m. This layer is unlikely to be affected by a single rider and may fail under larger loads, such as a cornice fall or snowmobile.

Confidence

Moderate

  • Uncertainty is due to the limited number of field observations.
  • Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Avalanche Summary

On Friday, an explosive triggered size 1.5 persistent slab avalanche was reported on a northerly aspect at treeline near Invermere. The slab failed on a crust down 80 to 110 cm.

Several rider-triggered wind slabs up to size 1.5 have occurred in the last 3 days on northerly aspects at treeline.

Snowpack Summary

30–50 cm of recent snow combined with strong southwest winds has formed slabs over a 3–5 cm thick crust, which is present up to approximately 2100 m.

A thick mid-November crust is buried 70–110 cm deep in eastern terrain, and up to 180 cm in areas with a deeper snowpack. In most areas, faceted grains overlie the crust. Specific, sheltered terrain features have surface hoar present on the crust or up to 30 cm above it.

Depth hoar (large, weak crystals) are present at the base of the snowpack.

Weather Summary

Sunday Night
Partly cloudy. 2 to 4 cm of snow. 20 km/h southwest ridgetop wind. Treeline temperature -7 °C. Freezing level 200 m.

Monday
Mix of sun and clouds. 2 to 4 cm of snow. 20 km/h southwest ridgetop wind. Treeline temperature -7 °C. Freezing level 700 m.

Tuesday
Mix of sun and clouds. 1 to 5 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -6 °C. Freezing level 400 m.

Wednesday
Mostly cloudy. 5 to 15 cm of snow. 20 km/h south ridgetop wind. Treeline temperature -6 °C. Freezing level 100 m.

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.
  • Be mindful that deep instabilities are still present in the snowpack.

Régions couvertes