Bulletin d’avalanche

Northwest Coastal

Apr 18 – 19, 2025Avalanche Canada
Voir sur la carte
Archivé · expiré last year

Danger d’avalanche

Sun
Mon
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
Ouvrir la carte complète

Points saillants

Weak layers in the snowpack continue to be a concern. A cautious approach is recommended, especially in high-elevation, north terrain where the snowpack remains most complex.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Newly formed wind slabs may be reactive to human triggers.

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–2.5

    Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

  • Persistent Slabs

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

    Weak layers from February and March remain reactive in the snowpack, but likely need a heavy trigger to cause a failure. These layers are most likely to be triggered on high north-facing terrain.

Confidence

Moderate

Avalanche Summary

On Thursday, natural wet loose avalanches up to size 2 were observed on all aspects at treeline and in the alpine.

Natural wind slabs up to size 3 were observed earlier in the week before the warming event. Some of these stepped down to persistent weak layers in the middle of the snowpack.

Snowpack Summary

A widespread surface crust is expected to have formed following Thursday's warming event. The new snowfall on Friday and Saturday is expected to be redistributed by moderate winds in wind-exposed terrain.

Three layers of note currently exist in the mid-snowpack and still have the potential to cause large avalanches:

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

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

  • 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.

Weather Summary

Friday Night

Cloudy with snowfall up to 6 cm. 30 to 50 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level valley bottom.

Saturday

Mostly cloudy with lingering flurries in the morning, 1-3 cm. 20-30 km/h west ridgetop wind. Treeline temperature -3 °C. Freezing level 1200 m.

Sunday

A mix of sun and cloud. 10 to 20 km/h northwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1300 m.

Monday

Mostly cloudy. 20 to 30 km/h west ridgetop wind. Treeline temperature -4 °C. Freezing level 1200 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.
  • Cornice failures could trigger large and destructive avalanches.

Régions couvertes