Bulletin d’avalanche

Northwest Coastal

Mar 31 – Apr 1, 2025Avalanche Canada
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Archivé · expiré 2 years ago

Danger d’avalanche

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

Human-triggered persistent slab avalanches are still possible in the alpine and treeline where a thick crust does not exist.

Stick to low-angle terrain away from overhead hazard.

Problèmes avalancheux

  • Wind Slabs

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

    Southeasterly winds will continue to redistribute loose snow into wind slabs.

    Cornices are large and looming, give them space.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–3.5

    Several weak layers persist in the snowpack. These layers continue to produce large avalanches and have been triggered remotely from some distance away.

Confidence

Moderate

Avalanche Summary

On Sunday, warmer temperatures and sunshine triggered a few natural cornice falls, pulling slabs on the slopes below up to size 2.5. Wet loose were also reported up to size 1.5 from steep sunny slopes. Evidence of large persistent slab avalanches (from last week) continue to be reported. Many failed on the buried persistent weak layers.

Where a thick, supportive surface crust is found, we expect that triggering avalanches on buried weak layers is unlikely.

Snowpack Summary

Variable wind affect and wind slab covers open terrain at upper elevations. A crust is found up to 1400 m and higher on solar slopes. New surface hoar up to 10 mm has formed on treeline and alpine features sheltered from the sun and wind.

Three layers of concern currently exist in the upper-mid snowpack. Surface hoar and a crust that formed in mid-March can be found 30 to 70 cm below the snow surface. Below this, another layer of surface hoar that formed in early March can be found at a depth of 60 to 100 cm. Additionally, a layer of facets, surface hoar, and/or a crust from mid-February is buried 120 to 200 cm deep.

The remainder of the snowpack is well consolidated, and there are no current concerns.

Weather Summary

Monday Night

Clear periods. 20 to 25 km/h northeast ridgetop wind. Treeline temperature -5 °C. Freezing level valley bottom.

Tuesday

Mix of sun and cloud. 15 to 30 km/h north ridgetop wind. Treeline temperature -4 °C. Freezing level 900 m.

Wednesday

Mix of sun and cloud. 15 to 30 km/h northwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1200 m.

Thursday

Mix of sun and cloud. 10 to 25 km/h west ridgetop wind. Treeline temperature -1 °C. Freezing level 1400 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.
  • Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
  • Cornice failures could trigger large and destructive avalanches.
  • Avoid steep, sun-exposed slopes when the air temperature is warm or when solar radiation is strong.

Régions couvertes