Bulletin d’avalanche

Northwest Coastal

Apr 22 – 23, 2025Avalanche Canada
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Archivé · expiré last year

Danger d’avalanche

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

Buried weak layers remain a concern, particularly in northerly alpine terrain.

Problèmes avalancheux

  • Wind Slabs

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

    Southwest wind and some new snow may form slabs in lee terrain features.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    3–5

    Buried weak layers from February and March remain reactive in the snowpack, but likely need a heavy load to trigger them. Avalanches are most likely in north-facing alpine terrain.

Confidence

Moderate

Avalanche Summary

A few small loose avalanches and cornices were observed on Monday.

On Sunday, cornice failures triggered two very large (size 3 to 5) natural persistent slab avalanches. There were multiple step-downs visible in the crowns, and these avalanches likely failed on the weak layers described in the Snowpack Summary.

Cornices continue to be a prime suspect for triggering large, destructive avalanches.

Snowpack Summary

A bit of new snow will fall onto a melt-freeze crust everywhere except for high elevation northerly aspects, where dry snow prevails. Southwest wind will continue to blow any available snow into lee terrain features in the high alpine.

Three weak layers may be found in the middle of the snowpack:

  • A layer of surface hoar and a crust that formed in mid-March is 50 to 80 cm below the snow surface.

  • A layer of surface hoar that formed in early March is buried 70 to 120 cm.

  • A layer of facetted grains and a crust that formed mid-February is buried 120 to 200 cm deep.

The remainder of the snowpack is consolidated.

Weather Summary

Tuesday Night

Cloudy with 2 to 5 cm of snow. 20 to 40 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 900 m.

Wednesday

Cloudy with 1 to 3 cm of snow. 20 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level 1100 m.

Thursday

A mix of sun and cloud. 20 to 30 km/h south ridgetop wind. Treeline temperature +1 °C. Freezing level 1500 m.

Friday

Cloudy with 10 to 20 cm of snow. 20 to 40 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 1300 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be aware of the potential for large, destructive avalanches due to deeply buried weak layers.
  • Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Régions couvertes