Bulletin d’avalanche

Northwest Inland

Jan 27 – 28, 2023Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Sun
Mon
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Uncertainty remains with buried weak layers. Avoid high-consequence avalanche terrain and use caution traveling in wind-loaded, shallow, rocky start zones.

Problèmes avalancheux

  • Wind Slabs

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

    At higher elevations (2000 m and above), where the recent precipitation fell as snow, strong southwest winds have formed windslabs on lee slopes and terrain features.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1.5–3

    Triggering persistent slab avalanches remains possible due to several weak layers in the top metre of the snowpack. Facet layers are the primary concern in alpine terrain, while preserved surface hoar layers are the concern in treeline terrain.

    In the north of the region, the lower snowpack remains weak and heavily faceted. Large triggers such as cornice failure or smaller avalanches stepping down to this layer are possible.

Confidence

Moderate

Avalanche Summary

An avalanche cycle likely occurred Wednesday, with rain, snow, and high winds. Both loose wet and wind slab releases have been reported in neighboring regions. While it is suspected some of the avalanche activity may have stepped down to deeper weak layers.

Snowpack Summary

At higher elevations, above roughly 2000 m, new snow has been redistributed by strong southwest winds. At lower elevations expect to find a widespread rain crust on the surface or moist, saturated snow at low elevations that are still experiencing above-freezing temperatures.

Several persistent weak layers may be found in the top meter of the snowpack. Most prominently, a layer of surface hoar buried in early January is now 20-50 cm deep and is reactive to skier traffic. A weak layer of facets and/or surface hoar buried in late December is now down 70-110 cm.

In the north of the region, the lower-depth snowpack remains weak and heavily faceted.

Weather Summary

Thursday night

Cloudy with isolated flurries and trace accumulation. Treeline temperatures -5 to -10 C. Moderate to strong west alpine winds. Freezing levels 1000 m.

Friday

Mostly sunny, with no precipitation. Treeline temperatures -5 to -10 C. Light to moderate north alpine winds. Freezing levels 700 m.

Saturday

Sunny, with no precipitation. Treeline temperatures -10 to -20 C. Light to moderate east alpine winds.

Sunday

Sunny, with no precipitation. Treeline temperatures -10 to -15 C. Light north alpine winds.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Extra caution for areas experiencing rapidly warming temperatures for the first time.
  • Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.

Régions couvertes