Bulletin d’avalanche

North Rockies

Apr 1 – 2, 2022Avalanche Canada
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Archivé · expiré 5 years ago

Danger d’avalanche

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

Points saillants

Fresh wind slabs may be reactive to human triggering at upper elevations, especially where they sit above a crust. 

Problèmes avalancheux

  • Wind Slabs

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

    New snow and strong southwest winds may build fresh and reactive wind slabs. Wind slabs can be expected in leeward terrain features in the alpine and treeline. These wind slabs will be most reactive where they overlie a slick crust.  

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–3

    Springtime cornices are large, weak and unpredictable. Give them a wide berth when traveling at ridge crest and avoid overhead exposure.

Confidence

Moderate - Forecast precipitation (either snow or rain) amounts are uncertain.

Weather Forecast

Unsettled weather is forecast for the weekend. This will bring mostly cloudy skies, new snow of 5-10 cm, and moderate to strong southwest winds at ridgetop. Freezing levels will rise to 1500 m during the day and drop overnight. 

Avalanche Summary

No new avalanches were reported on Thursday.

On Wednesday in the Renshaw area, several natural wind slab avalanches were reported and machine-triggered slabs up to size 1.

Snowpack Summary

Above 2000 m, 10-20 cm of new snow overlies 20 cm of denser snow that tapers rapidly with elevation. Below 2000 m a melt-freeze crust exists on all aspects and to mountain top on solar aspects. Below the crust, the top 10-30 cm of the snowpack is moist. This brings 50-60 cm over the mid-March interface at upper elevations. 

Westerly winds have formed reactive wind slabs on leeward terrain in the alpine and exposed treeline terrain.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.

Régions couvertes