Bulletin d’avalanche

Lizard-Flathead

Feb 22 – 23, 2023Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré

Points saillants

25-35 cm of recent snow and northerly winds have formed fresh wind slabs that are sitting on hard surfaces. Reactive wind slabs may be found on aspects that are generally windward, so be on the lookout for wind slabs on most aspects in open terrain.

Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1.5–3

    25-35 cm of recent snow and northerly winds have formed fresh wind slabs that are sitting on hard surfaces. Reactive wind slabs may be found on aspects that are generally windward, so be on the lookout for wind slabs on all aspects in open terrain.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2.5–3.5

    A layer of large, weak basal facets exists and remains a primary problem in shallow snowpack areas, like the Flathead range, and Elkford area.

Confidence

Moderate

Avalanche Summary

Numerous naturally triggered storm slab avalanches up to size 2.5 were reported primarily in the alpine on Tuesday. Several skier triggered storm slab avalanches up to size 1.5 were also reported.

Recently formed storm slabs will likely remain reactive to human triggers; especially in open areas where the wind has stiffened the snow.

The deep persistent slab problem continues to be a concern for parts of the region. In the nearby Bull River area, this very large older avalanche was observed on Friday by the Avalanche Canada field team which is expected to have occurred on Wednesday.

Snowpack Summary

25-35 cm of recent snow and northerly winds have formed fresh wind slabs that are sitting on hard surfaces. Reactive wind slabs may be found on aspects that are generally windward, so be on the lookout for wind slabs on all aspects in open terrain.

The middle of the snowpack is well consolidated and sits on a thick crust. The bottom of the snowpack still consists of weak, sugary crystals that are slowly gaining strength in areas with a deeper snowpack.

Deep persistent slab avalanches should still be on your radar in thinner snowpack areas outside of the Lizard Range such as the Elkford area, and the Flathead range.

Weather Summary

Tuesday night

Cloudy with isolated flurries; 0-3 cm / Moderate, east ridgetop wind / Low temperature at treeline around -30 C.

Wednesday

Mostly cloudy / Moderate, east ridgetop wind / High temperature at treeline around -22 C.

Thursday

Mix of sun and cloud / Strong, southeast ridgetop wind / High temperature at treeline around -25 C.

Friday

Sunny / Strong, west ridgetop wind / High temperature at treeline around -17 C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • Avoid travelling on slopes below cornices.

Régions couvertes