Bulletin d’avalanche

Northwest Coastal

Jan 7 – 8, 2024Avalanche Canada
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Archivé · expiré 3 years ago

Danger d’avalanche

Tue
Wed
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Assess for wind-affected snow before committing to consequential terrain.

A buried crust could make wind slabs more reactive to rider triggering.

Problèmes avalancheux

  • Wind Slabs

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

    Recent variable winds have built triggerable slabs on many aspects; near ridgetop, in cross-loaded areas and on steep rollovers.

    In the north, it may be possible to trigger slabs that fail on a deeper weak layer, up to 100 cm deep.

Confidence

Moderate

Avalanche Summary

Recent winds have built triggerable slabs on many aspects.

Friday, near Ningunsaw, skiers were able to trigger size 1-2 avalanches on west and southwest-facing slopes in the alpine and treeline, between 20 and 50 cm deep. One failed up to 100 cm deep. It is suspected to have failed on the weak layer described in the Snowpack Summary.

Wind slab avalanches were also triggered by skiers on Thursday near Terrace, up to 50 cm deep on north and east-facing convexities at treeline.

Snowpack Summary

Storm totals have reached 20 to 60 cm, greatest in the west of the region. Varied winds have blown this new snow into deeper and touchier deposits on a variety of aspects.

This snow overlies a melt-freeze crust which extends up to 1600 m. Newly formed slabs may not be well bonded to this crust.

In the North of the region, there may be a deeper crust that could act as a weak layer, buried up to 100 cm deep.

South, and closer to Terrace, the remainder of the snowpack is reportedly strong with various hard crusts. Check out this MIN report describing conditions in the backcountry near Shames.

Snow depths are highly variable throughout the region, ranging from 100 to 300 cm at treeline and tapering rapidly below.

Weather Summary

Saturday Night

Partly cloudy with a trace of snow in the southwest, north alpine wind 10 to 20 km/h, treeline temperature -5 ºC.

Sunday

A mix of sun and cloud with no precipitation, northwest alpine wind 10 to 20 km/h, treeline temperature -9 ºC.

Monday

Cloudy with 5 to 10 cm snow, southwest alpine wind 20 to 40 km/h, treeline temperature -6 ºC.

Tuesday

Partly cloudy with no precipitation, north alpine wind 20 to 30km/h, treeline temperature -8 ºC.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Carefully evaluate steep lines for wind slabs.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Choose low-angled, sheltered terrain where new snow hasn't been wind-affected.

Régions couvertes