Bulletin d’avalanche

Northwest Coastal

Feb 22 – 23, 2022Avalanche Canada
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Archivé · expiré 5 years ago

Danger d’avalanche

Thu
Fri
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Large, human-triggered wind slab avalanches have been reported in recent days. The most likely place to trigger an avalanche is in the alpine, on unsupported or convex terrain where the slope rolls away from you. Don't get surprised!

Problèmes avalancheux

  • Wind Slabs

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

    Wind direction has varied from southwest to northeast, now to northwest. The freshest wind slabs may be found on atypical aspects and features due to reverse-loading. Slabs heave been reactive and slide surprisingly far on the underlying crust. The most likely place to trigger a wind slab is near ridge crest and on unsupported or convex terrain features, where the slope rolls away from you.

Confidence

High -

Weather Forecast

Monday night: Clear, strong outflow winds, low of -16.

Tuesday: Increasing cloud, wind easing to light northwest, alpine high of -8.

Wednesday: Mostly cloudy with flurries up to 5 cm, moderate northwest wind, alpine high of -6.

Wednesday: Sunny, light northwest wind, alpine high of -4.

Avalanche Summary

On Sunday, natural size 2.5 wind slab avalanches were reported east of Kitimat.

On Saturday, several skiers were surprised by a handful of separate incidents of accidentally and remotely triggered size 2-2.5 (large) storm slabs, including the one reported in this MIN. These avalanches slid on the thick crust beneath the most recent storm snow. At least one was on a previously skied slope. Near Shames, storm slab activity included a few natural size 1s on solar aspects and skier triggered size 1.5s on convex slopes.

 

Snowpack Summary

In the alpine, 30-50 cm of recent, wind-affected snow appears to be bonding poorly to the underlying crust. Below 1300 m, formerly moist snow is refreezing in the cold temperatures.

The 10-30 cm thick rain crust beneath the recent snow effectively caps the underlying snowpack, making human triggering of avalanches on deeper weak layers very unlikely.

Terrain and Travel

  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Wind slabs may be poorly bonded to the underlying crust.

Régions couvertes