Bulletin d’avalanche

North Rockies

Mar 20 – 21, 2023Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Wed
Thu
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Points saillants

Lingering wind slabs may remain reactive to human triggers in isolated locations at upper elevations.

Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.

Problèmes avalancheux

  • Wind Slabs

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

    Lingering wind slabs may remain reactive to human triggers in isolated locations at upper elevations.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Strong solar radiation will increase the likelihood of wet loose avalanches on sunny aspects in the alpine.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    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

Moderate

Avalanche Summary

Numerous size 1-1.5 wet loose avalanches triggered by solar radiation were reported on sunny aspects at all elevations on Sunday.

Snowpack Summary

Expect to find a melt-freeze crust on the surface of all aspects at treeline and below and on sunny aspects in the alpine. Solar radiation will break down the crust on sunny slopes throughout the day.

Lingering wind slabs may remain reactive to human triggers in isolated locations at upper elevations.

The middle of the snowpack is generally well-settled and strong.

A weak layer of large facets is found near the base of the snowpack. This layer is of most significant concern in shallow snowpack areas in the north and east of the region. The most likely areas to trigger this layer are shallow, rocky areas or where the snowpack transitions from thin to thick.

Weather Summary

Monday Night

Clear skies / 20 km/h east ridgetop wind / Temperature at treeline around -10 C / Freezing level valley bottom

Tuesday

Sunny / 20 km/h west ridgetop wind / Temperature at treeline around -1 C / Freezing level 1800 m

Wednesday

Mix of sun and cloud / 30 km/h southwest ridgetop wind / Temperature at treeline around -4 C / Freezing level 1600 m

Thursday

Mostly sunny / 30 km/h southwest ridgetop wind / Temperature at treeline around -3 C / Freezing level 1700 m

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Cornice failure may trigger large avalanches.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

Régions couvertes