Bulletin d’avalanche

Purcells

Dec 14 – 15, 2023Avalanche Canada
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Archivé · expiré 3 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
1 · Faible
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Points saillants

Choose conservative terrain, weak layers in the mid and lower snowpack remain primed for human triggering.

Problèmes avalancheux

  • Wind Slabs

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

    Recent winds have built reactive wind slabs in north and east-facing terrain features.

  • Persistent Slabs

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

    Surface hoar is most likely to be found at treeline elevations, and most triggerable where the rain crust (40-60 cm deep) disappears

    Weak facets sit at the base of the snowpack, recent avalanches have failed on or stepped down to this layer

Confidence

Moderate

Avalanche Summary

On Tuesday, numerous wet loose avalanches were reported on steep, south-facing slopes up to size 1. Explosive control was able to trigger a size 2 deep persistent slab that ran on the buried weak layer of surface hoar and facets.

Human-triggered avalanches are likely at treeline and in the alpine.

Snowpack Summary

Variable snow surfaces exist including new surface hoar development and wind affected snow. Down 30-45 cm exists a rain crust. This has been observed up to 1900 m near Golden and 2200 m near Invermere.

A concerning layer of surface hoar is now buried 40-70 cm deep.

The middle and base of the snowpack holds large, weak snow crystals. A hard crust may be found near the ground.

Treeline snowpack depths are variable and generally range between 60 and 110 cm. Snowpack tapers rapidly as you move lower in elevation.

Weather Summary

Wednesday Night

Cloudy with new snow 5-10 cm. Ridgetop wind 20-30 km/h and temperatures near -5 C. Freezing level valley bottom.

Thursday

Cloudy with a trace of new snow. Ridgetop wind 20-30 km/h and temperatures near -3 C. Freezing level near 1600 m.

Friday

A mix of sun and cloud. Ridgetop wind 20 km/h and temperatures near -2 C. Freezing levels 1500 m.

Saturday

Mix of sun and cloud. Ridgetop wind light and temperatures near -4 C. Freezing level valley bottom but an alpine temperature inversion may exist.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Stay off recently wind loaded slopes until they have had a chance to stabilize.
  • Make conservative terrain choices and avoid overhead hazard.
  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.

Régions couvertes