Bulletin d’avalanche

North Rockies

Dec 5 – 6, 2024Avalanche Canada
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Archivé · expiré 2 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré

Points saillants

Minimize exposure to avalanche terrain. Rapidly changing weather has created complex and dangerous conditions.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1.5–2.5

    Strong winds are expected to build deep, reactive wind slabs near ridgelines and steep open terrain. Mild temperatures could increase their reactivity.

  • Loose Wet

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

    Rain and above-freezing temperatures will weaken surface snow in steep terrain, potentially affecting all elevations.

Confidence

Low

Avalanche Summary

Limited observations suggest wet loose avalanches have occurred since the warming began earlier this week, and shooting cracks were observed in the top 30 cm of storm snow near McBride on Wednesday.

Given the dramatic weather fluctuations, we suspect some natural avalanches occurred on Tuesday and Wednesday, particularly on wind-loaded alpine slopes and rain-soaked slopes. Human-triggered avalanches remain likely under these conditions.

Snowpack Summary

Surface conditions are rapidly changing after last weekend’s snowfall, with 40 to 80 cm of storm snow settling quickly due to warming and rain. The deepest amounts are in Pine Pass and McGregor areas. Recent snow presents several potential weaknesses including wet snow from warming and wind slabs from strong winds. There may also be a poor bond to underlying layers, especially in the northern Cariboos and Renshaw areas, though data is limited.

The lower snowpack contains a widespread crust from early-November, possibly with weak facets around it. Its distribution and reactivity are unclear, and it is uncertain if avalanches are failing on this layer.

Treeline snow depths range from 60 to 200 cm.

Weather Summary

Wednesday Night

Mostly cloudy with light rain/snow. 40 km/h southwest ridgetop wind. Treeline temperatures around 0 °C. Freezing level drops from 2500 to 1500 m.

Thursday

Mostly cloudy with light rain and 1 to 3 cm of snow. 40 to 60 km/h southwest ridgetop wind. Treeline temperature around 0 °C. Freezing level fluctuates between 1500 and 2000 m.

Friday

Cloudy with precipitation increasing in intensity throughout the day. Pine Pass and McGregors expect 15 to 25 cm of snow above 1000 m, McBride area expect 5 to 10 cm of snow above 1200 m, eastern slopes expect less than 5 cm above 1400 m. 50 to 70 km/h southwest ridgetop wind. Treeline temperature around -1 °C. Freezing level around 1500 m.

Saturday

Mostly cloudy with 5 to 10 cm of snow (except 1 to 3 cm of snow on the eastern slopes). 40 to 60 km/h southwest ridgetop wind. Treeline temperature around -2 °C. Freezing level around 1300 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Use conservative route selection and resist venturing into complex terrain.
  • Avoid freshly wind-loaded terrain features.
  • Seek out sheltered terrain where new snow hasn't been affected by wind.
  • A moist or wet snow surface, pinwheeling, and natural avalanches are all indicators of a weakening snowpack.

Régions couvertes