Bulletin d’avalanche

North Columbia

Mar 16 – 17, 2020Avalanche Canada
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Archivé · expiré 7 years ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

Expect an upward swing in temperatures as the freezing level rises on Monday. Be especially cautious underneath steep sun exposed slopes and around rock outcrops.

Problèmes avalancheux

  • Wind Slabs

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

    Moderate to strong northeast wind formed wind slabs at all elevations which are reactive to human triggers. 

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1.5–3.5

    A weak layer of surface hoar is buried 60-100 cm deep. Even though avalanche reports decreased over the past week it might still possible to human-trigger. The distribution of this problem extends to all aspects and elevations, but north to east aspects near treeline have been a hot-spot for reactivity.

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

SUNDAY NIGHT: Mainly clear, light northeast wind, alpine temperature -8 C.

MONDAY: Clear skies, light north wind, alpine temperature -4 C, freezing level 1400 m.

TUESDAY: Mix of sun and cloud, light northwest wind, alpine temperature -4 C, freezing level 1500 m.

WEDNESDAY: Mix of sun and cloud, light northwest wind, alpine temperature -6 C, freezing level 1200 m.

Avalanche Summary

Recent reports from this weekend show several natural wind slab avalanches ranging in size from 1.5 to 3 running in the alpine on northeast, south and southeast aspects at treeline and in the alpine. 

Snowpack Summary

Moderate to strong northeast wind has redistributed into alpine and tree line lee terrain. Recent new snow from last week may sit on a surface hoar layer and a sun crust on steep solar aspects. 

A widespread weak layer of surface hoar buried at the end of February is 60-100 cm deep. On solar aspects, this layer may sit over a crust. There is a low likelihood of triggering an avalanche on this layer, but the consequences of doing so would be high. Read more about surface hoar on our forecaster blog.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Be aware of the potential for large avalanches due to the presence of buried surface hoar.
  • Minimize exposure to steep, sun exposed slopes, especially when the solar radiation is strong.

Régions couvertes