Bulletin d’avalanche

Northwest Inland

Feb 14 – 15, 2023Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

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

Points saillants

Expect to find wind slabs in lee terrain features.

Problèmes avalancheux

  • Wind Slabs

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

    Riders could trigger wind slabs in lee terrain features from recent snow and strong southwest wind. Assess for slab properties in steep and consequential terrain before committing.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    2–3

    It remains possible that riders could trigger various buried layers. The most likely terrain feature to trigger them is within upper treeline and alpine elevations in shallow, rocky start zones.

Confidence

Moderate

Avalanche Summary

Poor visibility led to only a few avalanche observations over the weekend, including evidence of a natural cycle of large (size 2 to 3) wind slabs in lee terrain features in the alpine. We anticipate receiving more avalanche observations as the clouds clear.

Looking ahead, riders could still trigger wind slabs in lee terrain features as they slowly bond to the snowpack. There is also a possibility of triggering deeper layers described in the Snowpack Summary.

Snowpack Summary

Variable snowfall amounts accumulated across the region over the weekend but most areas received around 20 cm with strong southwest wind. The wind scoured wind-exposed terrain and formed wind slabs in lee terrain features.

A melt-freeze crust is found about 80 cm deep, with reported good bonding to it. An old surface hoar layer from early January may be found about 100 to 150 cm. Neither of these layers have produced recent avalanches.

Weather Summary

Monday Night

Clear skies with no precipitation, 20 km/h northwest wind, treeline temperature -13 °C.

Tuesday

Mix of sun and cloud with no precipitation, 20 km/h west wind, treeline temperature -11 °C.

Wednesday

Cloudy with snowfall, accumulation 5 to 10 cm, 40 to 60 km/h southwest wind, treeline temperature -9 °C.

Thursday

Cloudy with snowfall then clearing, accumulation 5 to 10 cm, 20 km/h west wind, treeline temperature -9 °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.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Avoid areas with a thin or variable snowpack.

Régions couvertes