Bulletin d’avalanche

Yukon

Apr 24 – 25, 2022Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Tue
Wed
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
Sans niveau

Points saillants

Make observations as you travel and be on the lookout for signs that suggest unstable snow. Expect snow conditions to change quickly with elevation, aspect, and time of day.

Problèmes avalancheux

  • Wind Slabs

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

    Recent snowfall and southerly winds may have formed pockets of wind slabs in lee areas in the alpine.

    Use caution entering lee terrain features below ridges. The snow could slide easily where it rests on a hard melt-freeze crust, surface hoar, or facetted snow. 

  • Cornices

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

    Cornices may be weak and reactive to human triggers. They are a significant hazard alone and may produce large slab avalanches as they fall onto the slope below. Cornice falls are more likely as temperatures warm each day, or when strong sunshine is present. 

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

SUNDAY NIGHT: Mainly cloudy with light flurries. Freezing level lowering to 700 m. Light southeasterly winds. 

MONDAY: Partially cloudy with isolated flurries. Freezing level rising to 1500 m in the afternoon. Light northerly winds.

TUESDAY: A mix of sun and cloud with light flurries in the morning. Freezing level rising to 1500 m in the afternoon. Light northerly winds.

WEDNESDAY: Cloudy with flurries. Freezing level rising to 1400 m in the afternoon. Light southerly winds.

Avalanche Summary

A large cornice failure was observed in the Cleveland area on Thursday. The full report can be seen here.

Check out this MIN report for a picture of recent conditions in the White Pass.

Reports are limited at this time of year, but we suspect pockets of wind slabs exist in lee areas in the alpine. Small wet loose avalanches are possible on steep solar aspects if the sun comes out on Monday. Please let us know what you're seeing by filling out a MIN report!

Snowpack Summary

5-10 cm of recent snowfall may have been redistributed by southerly winds into wind slabs lee areas in the alpine and exposed treeline. This new snow is expected to bond poorly to the faceted and heavily wind-affected surface from last week's strong northerly winds. Large surface hoar has also been found in sheltered alpine areas. A surface crust can be found on all aspects to at least 1400 m and to mountain top on solar aspects. The mid-snowpack is generally strong, overlying weak basal facets at the base of the snowpack. 

Check out this MIN report from the Yukon Field Team for a picture of conditions prior to the weekend's storm.

Terrain and Travel

  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep 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.

Régions couvertes