Bulletin d’avalanche

Purcells

Dec 24 – 25, 2023Avalanche Canada
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Archivé · expiré 3 years ago

Danger d’avalanche

Tue
Wed
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
1 · Faible

Points saillants

Numerous, large persistent slab avalanches have been reported in the northern portion of this region in recent days.

Conservative terrain choices will be the key to playing safe.

Problèmes avalancheux

  • Wind Slabs

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

    5-15 cm of new snow on Saturday and moderate southwest wind have formed fresh wind slabs on lee features at treeline and above.

  • Persistent Slabs

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

    The primary layer of concern in much of this region is a weak layer of surface hoar down 50-70 cm. This layer may be less likely to trigger in areas that have a strong, supportive crust above.

Confidence

Moderate

Avalanche Summary

There have been numerous natural and skier triggered very large(up to size 3) persistent slab avalanches reported on all aspects at treeline and above in the Esplanade range over the past week. They have been failing on a weak layer of surface hoar down 50-70 cm.

This weak layer is a concern throughout much of the region.

Snowpack Summary

5-15 cm of new snow on Saturday and moderate southwest wind have formed fresh wind slabs on lee features at treeline and above.

The primary layer of concern in much of this region is a weak layer of surface hoar down 50-70 cm. This layer may be less likely to trigger in areas that have a strong, supportive crust above.

In the southern portion of the region, weak facets near the ground may be the primary layer of concern. Especially in shallow, rocky areas in the alpine.

Average snowpack depths at treeline are 70-120 cm which tapers rapidly below treeline.

Weather Summary

Saturday Night

Clear skies, west alpine wind 10 to 20 km/h, treeline temperature -8 °C.

Sunday

Sunny skies, southwest alpine wind 10 to 20 km/h, treeline temperature -10 °C.

Monday

Sunny skies, southwest alpine wind 10 to 20 km/h, treeline temperature -10 °C.

Tuesday

Mix of sun and cloud, west alpine wind 30 to 40 km/h, treeline temperature -8 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.
  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
  • Surface hoar distribution is highly variable. Avoid generalizing your observations.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Régions couvertes