Bulletin d’avalanche

Northwest Coastal

Avalanche Canada
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Danger d’avalanche

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

Points saillants

Storm slab releases are more likely at upper elevations in exposed terrain where wind has supported slab development.

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

Problèmes avalancheux

  • Persistent Slabs

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

    Persistent weak layers of crust/facets or surface hoar are buried in the upper 250 cm of the snowpack. Distribution seems spotty and signs of instability may not be evident. The best defence is choosing smaller, low-consequence terrain.

  • Storm Slabs

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

    New snow and moderate northwest wind are building storm slabs at upper elevations. Storm slabs are likely to be more reactive in a-typical lee terrain features from reverse loading. Buried old wind slabs may also remain reactive.

Confidence

Moderate

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

Avalanche Summary

On Monday, a size 1 storm slab was reported north of Silvertip. It occured in a wind affected area and the depth was 20 cm.

We suspect similar activity occurred throughout the region and specifically the Kispiox Range where storm snow accumulated over 20 cm during the day Monday.

Numerous wet loose avalanches were reported on Monday during the rise in freezing levels.

Persistent slab activity has tapered in the last week, but the snowpack structure remains suspect.

Snowpack Summary

Recent storm snow has accumulated between 30 to 60 cm at upper elevations. Freezing levels have been fluctuating, moist and/or refrozen snow is expected at treeline and below. This new snow has been redistributed by moderate northwest wind creating more reactive storm slabs in lee features.

This further buries various previous surfaces: a sun crust on solar aspects, faceted snow in sheltered northerly aspects and surface hoar.

Below this, A layer of facets and/or surface hoar from earlier in March can be found 50 to 100 cm deep.

Several persistent weak layers are buried up to 250 cm deep. While triggering these layers is becoming unlikely, they present a low-probability, high-consequence problem.

Weather Summary

Monday Night
Mostly cloudy. 2 to 10 cm of snow. 40 km/h northwest ridgetop wind. Treeline temperature -5 °C.

Tuesday
Cloudy. 1 cm of snow. 20 km/h northwest ridgetop wind. Treeline temperature -4 °C.

Wednesday
Mix of sun and clouds. 1 to 2 cm of snow. 30 km/h northwest ridgetop wind. Treeline temperature -5 °C.

Thursday
Mostly sunny. 1 cm of snow. 20 km/h northwest ridgetop wind. Treeline temperature -2 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Keep your guard up as storm slabs may remain sensitive to human triggering.
  • Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
  • Be aware of the potential for large, destructive avalanches due to deeply buried weak layers.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Régions couvertes