Bulletin d’avalanche

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Avalanche Canada
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Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
Périmé — ce bulletin a expiré 5 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Recent storm snow and strong winds are creating reactive wind slabs at upper elevations.

Continually assess as you travel, and stick to conservative terrain.

Problèmes avalancheux

  • Wind Slabs

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

    Recent snow and strong northwest wind are building fresh wind slabs above 1400 m in lee features like the downwind side of ridges, peaks, and terrain breaks. Wind slab avalanches may step down to deeper layers.

  • Persistent Slabs

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

    A persistent weak layer is buried 1 - 2 m. This is a low-probability, high-consequence problem. Signs of instability may not be obvious. The best defence is smaller, low-consequence terrain.

Confidence

Moderate

  • We are uncertain about how quickly the snowpack will recover and gain strength.

Avalanche Summary

On Monday, the field team observed a recent natural size 1 wind slab avalanche.

Going forward, there is 15 to 20 cm of snow available for transport with 50 km/h northwest winds in the forecast. Wind slabs are likely building in some a-typical terrain and human triggering is likely.

Snowpack Summary

Dropping freezing levels, continued flurries and strong wind are creating variable surface conditions:

  • At upper elevations above 1400 m, up to 20 cm of storm snow that has been redistributed by strong northwest winds.

  • At treeline and below roughly 5 to 7 cm of dry snow overlies moist and/or refrozen surfaces.

The most recent storm snow overlies wind-affected surfaces in exposed terrain and faceted snow in sheltered terrain.

A thick crust from late January can be found at a wide range of depths, from 75 to 150 cm. Where it is shallowest, facets are most likely to exist above it, and the more problematic it is expected to be.

We do not have concerns about the snowpack below this layer.

Weather Summary

Monday Night
Mostly cloudy. 2 to 5 cm of snow. 50 km/h west ridgetop wind. Treeline temperature -5 °C.

Tuesday
Cloudy. 30 km/h northwest ridgetop wind. Treeline temperature -5 °C.

Wednesday
Mix of sun and clouds. 1 cm of snow. 30 km/h northwest ridgetop wind. Treeline temperature -4 °C.

Thursday
Mostly sunny. 20 km/h northwest ridgetop wind. Treeline temperature -1 °C.

Wednesday




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.
  • Avoid lee and cross-loaded slopes at alpine and treeline elevations.
  • Be aware of the potential for large avalanches due to buried weak layers.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Régions couvertes