Bulletin d’avalanche

Blue River

Jan 8 – 9, 2024Avalanche Canada
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Archivé · expiré 3 years ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré

Points saillants

Recent storm snow is the main concern, but several lurking weak layers are making snowpack evaluation more complicated. Choose conservative terrain to simplify the equation.

Problèmes avalancheux

  • Persistent Slabs

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

    Two weak layers of surface hoar layers can be found in the top 1.5 m of the snowpack. These layers are getting harder to rider trigger but may be triggered by storm or wind slabs stepping down.

  • Storm Slabs

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

    20-40 cm of recent snow is settling over a variety of old surfaces that may keep storm slabs reactive to human triggering. Wind loaded areas and sheltered spots around treeline where surface hoar may be buried are the most suspect.

  • Deep Persistent Slabs

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

    Basal facets remain a real concern in steep, rocky terrain and other alpine features with thin-to-thick snowpack transitions.

Confidence

Moderate

Avalanche Summary

Numerous natural size 1-1.5 (small) storm slabs were observed in the Blue River area on Saturday. These appeared to involve only 20-30 cm of new snow. Skiers in the Trophy Range reported skier-triggered sluffing, rather than storm slabs, with 30-45 cm of new snow in that area. Improving visibility may allow a better look at whether any persistent or deep persistent slabs were triggered during or since Saturday's storm.

Snowpack Summary

Up to 50 cm of recent snow is settling and gradually bonding to a variety of surfaces. Sheltered terrain where it has buried surface hoar is where this bond is most suspect. The storm also buried a crust below 1600 m.

Two additional surface hoar layers in the top 1.5 m of the snowpack remain a concern. The deeper of the two likely has a robust crust above it below treeline.

The depth of the snowpack varies greatly throughout the region. Weak basal facets are present at the base of the snowpack.

Weather Summary

Sunday night

Becoming cloudy. Southwest alpine wind 5 to 10 km/h, increasing.

Monday

Mostly cloudy with a trace of new snow expected, increasing overnight. Southwest alpine wind 10 to 15 km/h, treeline temperature -11°C.

Tuesday

Cloudy with 10 to 20 cm of new snow expected, south alpine wind 20 to 40 km/h, treeline temperature -10°C.

Wednesday

Clearing. Northwest alpine wind 5-15 km/h. Treeline temperature -16°C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Régions couvertes