Bulletin d’avalanche

North Columbia

Mar 14 – 15, 2023Avalanche Canada
Voir sur la carte
Archivé · expiré 4 years ago

Danger d’avalanche

Thu
Fri
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
Ouvrir la carte complète

Points saillants

40-60 cm of recent snow and strong south winds formed reactive storm slabs at all elevations.

Make conservative terrain choices and use small low consequence slopes to test the bond of the new snow.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3

    40-60 cm of recent snow and strong south winds formed reactive storm slabs at all elevations.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–1.5

    Expect natural wet loose avalanches on steep sunny aspects when the sun comes out.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2.5–4

    A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth, but large triggers such as cornice failures or smaller avalanches in motion have the potential to produce very large avalanches with surprisingly wide propagation. Suspect terrain for human triggering includes steep, shallow, and rocky terrain where the snowpack transitions from thin to thick.

Confidence

High

Avalanche Summary

Monday was an active day in the mountains.

Numerous natural and rider triggered storm slab avalanches up to size 2 on a variety of aspects at all elevations were reported throughout the region. A few size 3 naturally triggered storm slabs were also reported in the alpine.

Additionally, a few size 2-2.5 storm slabs were remotely triggered by a helicopter landing. They were on north aspects at treeline near Coursier Lake.

Snowpack Summary

40-60 cm of recent snow and strong south winds formed reactive storm slabs at all elevations.

The storm slabs overlie a variety of surfaces, which include surface hoar (3-10 mm) on shady slopes at all elevations, wind affected surfaces at treeline and above, and sun crust on sunny aspects.

The mid-snowpack is generally strong but the lower snowpack is a different story.

The November facets are still prominent at the base of the snowpack. They are showing signs of improving but this layer remains a significant concern in rocky, shallow, or thin to thick snowpack areas at treeline and above.

Weather Summary

Tuesday Night

Partly cloudy / 10 km/h west ridgetop wind / Low temperature at treeline around -9 C / Freezing level valley bottom

Wednesday

Mix of sun and cloud with isolated flurries; 0-5 cm / 20 km/h west ridgetop wind / High temperature at treeline around -7 C / Freezing level 1300 m

Thursday

Sunny / 10 km/h northwest ridgetop wind / High temperature at treeline around -6 C / Freezing level 1500 m

Friday

Sunny / 10 km/h southeast ridgetop wind / High temperature at treeline around -4 C / Freezing level 1600 m

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Make conservative terrain choices and avoid overhead hazard.
  • Use small low consequence slopes to test the bond of the new snow.
  • Avoid exposure to slopes that have cornices overhead.
  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.

Régions couvertes