Bulletin d’avalanche

North Rockies

Dec 15 – 16, 2023Avalanche Canada
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Archivé · expiré 3 years ago

Danger d’avalanche

Sun
Mon
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Recent storm snow and buried weak layers may be primed for human triggering.

Avalanche danger will rise with new snow and wind Friday afternoon into Saturday.

Problèmes avalancheux

  • Wind Slabs

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

    Fresh wind slabs may be reactive to human triggering in upper elevations. The greatest reactivity may be found in wind-loaded areas where slabs overlie surface hoar or a crust.

  • Persistent Slabs

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

    Buried surface hoar is most likely to be found at treeline and above. Its most triggerable where the recent buried rain crust thins, or disappears at upper elevations.

Avalanche Summary

No new avalanche reports were submitted on Wednesday.

If you go out in the backcountry, please consider sharing your observations on the Mountain Information Network (MIN).

Snowpack Summary

Strong to extreme winds have likely stripped available snow from south and west-facing slopes, redistributing it onto north and east-facing terrain features. A new surface crust may extend up into treeline and possibly some alpine areas. New snow expected Friday night may have a poor bond to these firm surfaces.

A concerning layer of surface hoar can be found around 30-50 cm deep.

A crust with sugary facets beneath it can be found just above the ground. The snowpack is still shallow for this time of year. Average snowpack depths at treeline range from 65 to 90 cm.

Confidence

Low

Weather Summary

Thursday Night

Mostly clear skies. Ridgetop wind 20-40 km/h from the south and temperatures near -8 C. Freezing levels valley bottom.

Friday

Cloudy with snow starting midday for the 24 hour period. Ridgetop wind 40 to 70 km/h and temperatures near -7 C. Freezing levels 1000 m.

Saturday

New snow, 20-30 cm by the afternoon. Ridgetop winds 40-65 km/h from the west. Freezing levels rise to 1500m.

Sunday

Mostly cloudy with sunny periods. Ridgetop wind 30-45 km/h from the west and temperatures near -5 C. Freezing levels valley bottom.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
  • Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.

Régions couvertes