Bulletin d’avalanche

North Columbia

Mar 13 – 14, 2022Avalanche Canada
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Archivé · expiré 5 years ago

Danger d’avalanche

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

Points saillants

Recently formed storm slabs will likely be reactive to human triggers on Monday; especially in wind affected terrain.

Riders may be surprised by widely propagating avalanches at treeline and below where storm slabs are sitting on a weak layer of surface hoar.

Problèmes avalancheux

  • Storm Slabs

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

    20-40 cm of recent snow and moderate southwest winds formed fresh storm slabs that have been most reactive in wind affected terrain; especially where slabs are sitting on a weak layer of surface hoar or a sun crust.

Confidence

Moderate - Uncertainty is due to how buried persistent weak layers will react with the forecast incoming weather.

Weather Forecast

SUNDAY NIGHT: Snow(above around 700m); 5-10 cm / Moderate southwest winds / Low of -3 / Freezing level 1000 m.

MONDAY: Snow (above around 1300 m); 5-10 cm, and another 10-15 cm overnight / Moderate southwest wind / High of 1 / Freezing level 1600 m.

TUESDAY: Snow (above around1300 m); 5-10 cm, and another 10-15 cm overnight / Light southwest wind / High of 1 / Freezing level 1600 m.

WEDNESDAY: Mix of sun and cloud with isolated flurries; 0-3 cm / Light west wind / High of -1 / Freezing level 1400 m.

Avalanche Summary

Numerous natural and skier triggered storm slab avalanches up to size 2.5 were reported on Saturday. The storm slabs were most reactive were they were sitting on a sun crust or a weak layer of surface hoar.

Riders may get surprised by widely propagating storm slabs that are sitting on a weak layer of surface hoar.

Snowpack Summary

20-40 cm of recent snow and moderate southwest winds formed fresh storm slabs that have been most reactive in wind affected terrain; especially where slabs are sitting on a weak layer of surface hoar or a sun crust.

The 20-40 cm of recent snow is sitting on a variety of surfaces including hard wind affected snow, sun crusts on southerly slopes, and surface hoar on shady or sheltered slopes. 

The late February persistent weak layer combination of crust, facets and surface hoar is down 30-40 cm. Reports suggest this layer is not a problem in most areas.

Two persistent weak layers from mid February and late January are buried 50-120cm deep. No recent avalanches have been reported on these layers.

Terrain and Travel

  • Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
  • Be especially cautious as you transition into wind affected terrain.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.

Régions couvertes