Bulletin d’avalanche

Coquihalla

Feb 28 – Mar 1, 2025Avalanche Canada
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Archivé · expiré 2 years ago

Danger d’avalanche

Sun
Mon
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

Persistent weak layers are scary and will be more concerning in warm weather.

Rider-triggered avalanches are likely and could be very destructive.

Be mindful of overhead hazards.

Problèmes avalancheux

  • Wind Slabs

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

    Wind slabs remain sensitive to rider triggers in lee terrain, especially at higher elevations. Small wind slab releases may step down to weak layers in the upper snowpack to produce larger, more destructive avalanches.

  • Persistent Slabs

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

    There are indications of a destructive, persistent slab problem waking up in the Cascades. Wind-loaded areas at higher elevations are the most likely places to trigger this problem.

  • Loose Wet

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

    Surface snow may produce loose wet avalanches in steep terrain, particularly if the solar radiation is strong. Surface crust formation, where it occurs, will neutralize this problem.

Confidence

Moderate

Avalanche Summary

Small loose wet avalanches were observed on Wednesday from steep solar slopes in the Coquihalla.

Evidence of natural avalanches from the past weekend's storm is still visible throughout the region, with numerous very large (size 3.5 to 4) persistent slabs with impressive crowns (100 to 200 cm) in the Manning region.

Snowpack Summary

30 to 40 cm of rapidly settling storm snow is found at treeline and above. Wind-affected snow is present in lee features, while a sun crust is found on southerly slopes.

A weak layer of faceted snow or surface hoar is now buried 100 to 120 cm deep and present in higher elevations, particularly shaded terrain. Professionals are concerned about this layer waking up with the warm weather.

A crust from December exists buried more than150 cm deep, with facets around it in shallow areas.

At lower elevations, the snow is wet, heavy and water-saturated.

Weather Summary

Thursday Night

Cloudy with isolated flurries. 30 to 50 km/h southwest ridgetop wind. Treeline temperature +2°C. Freezing level around 2000 m.

Friday

Mix of sun and clouds. 10 to 20 km/h southwest ridgetop wind. Treeline temperature stable around +6°C. Freezing level rising to 2800 m.

Saturday

Mostly sunny. 30 to 40 km/h south ridgetop wind. Treeline temperature +6°C. Freezing level reaching 2800 m.

Sunday

Mostly cloudy. 10 to 20 km/h southwest ridgetop wind. Treeline temperature +2°C. Freezing level around 1500 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.
  • Be aware of the potential for large avalanches due to buried weak layers.
  • Avoid thin areas like rocky outcrops where you're most likely to trigger avalanches on deep weak layers.
  • Cornices often break further back than expected; give them a wide berth when traveling on ridgetops.

Régions couvertes