Bulletin d’avalanche

Microwave-Sinclair

Avalanche Canada
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Danger d’avalanche

Thu
Fri
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 4 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

The possibility of a large persistent slab avalanche means continuing to avoid large, steep, open slopes.

These avalanches may be hard to trigger, but the consequences would be serious.

Problèmes avalancheux

  • Wind Slabs

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

    A period of moderate winds and snowfall may create small, reactive wind slabs over a firm crust.

  • Persistent Slabs

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

    A layer of weak, sugary snow surrounding a firm crust is buried 100 to 200 cm deep. It seems to have been more likely to avalanche during warm, sunny weather, so it may be less reactive during this cooler, cloudy period.

Confidence

Moderate

  • We are uncertain about how quickly persistent slabs are gaining strength.

Avalanche Summary

A few large (up to size 3) natural persistent slab avalanches occurred as recently as April 10. One size 3 may have been remotely triggered. These large avalanches have occurred on northwest through east-facing slopes in the alpine.

Snowpack Summary

10-20 cm of recent snow has buried a strong, supportive crust that is expected on the surface on all aspects at treeline and on all but north-facing terrain in the alpine.

A possible period of moderate northeast wind may be loading this loose snow onto crusty southwest facing slopes.

Below treeline, a full overnight refreeze may not occur, resulting in a thin, weak, breakable crust. Wind-affected surfaces are likely in north-facing alpine terrain.

A layer of weak, sugary snow over a thick crust is buried 100 to 200 cm and continues to produce large, surprising avalanches.

Weather Summary

Tuesday Night

Mostly cloudy. 2 to 10 cm of snow. 20 km/h west ridgetop wind. Treeline low -6 °C.

Wednesday

Mostly cloudy. 1 to 3 cm of snow, possible hotspots of 10 cm. 30 km/h northeast ridgetop wind, decreasing to 10 km/h through the day. Treeline high -1 °C. Freezing level rising to 1400 m.

Thursday

Mix of sun and clouds. 1 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -2 °C.

Friday

Mostly sunny. 1 cm of snow. 20 km/h west ridgetop wind. Treeline temperature -3 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
  • Be aware of the potential for large avalanches due to buried weak layers.
  • Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
  • Pay attention to the wind; once it starts to blow, sensitive wind slabs are likely to form.

Régions couvertes