Bulletin d’avalanche

Yukon

Jan 22 – 23, 2022Avalanche Canada
Voir sur la carte
Archivé · expiré 5 years ago

Danger d’avalanche

Mon
Tue
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
Sans niveau

Points saillants

Strong winds, warming temperatures, and new snow are a recipe for dangerous avalanche conditions. 

Virtually all slopes are heavily wind affected, making for unwelcoming riding conditions.

Problèmes avalancheux

  • Wind Slabs

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

    An intense storm impacting the region has brought 15-30 cm of new snow to the White Pass, with continued snowfall expected throughout the day. The accompanying strong to extreme southerly winds and rising temperatures will continue to create deep deposits of wind slab in lee areas. 

  • Loose Wet

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

    This is mainly a concern for inland areas with a thin snowpack. If the sun comes out today, strong solar radiation compounded by warm temperatures may create wet loose avalanches on steep solar aspects. In shallow snowpack areas, wet loose avalanches have the potential to step down to the ground and entrain a large amount of mass.

Confidence

Moderate - Forecast snowfall amounts are uncertain. Uncertainty is due to the extreme variability of wind effect on the snowpack.

Weather Forecast

Friday Overnight: Snowing, 10-20 cm of accumulation in White Pass. Strong southwest winds. Freezing level around 600m.

Saturday: Continued snowfall, 5-10 cm of accumulation. Moderate to strong southwest winds. Freezing level 500-800m.

Sunday: Mainly cloudy, trace to 5 cm of new snow accumulation. Strong southerly winds. Freezing level 500m.

Monday: Partially cloudy, trace new snow. Moderate to strong southwest winds. Freezing level at the valley bottom.

Avalanche Summary

When the sun came out on Friday, several natural loose wet avalanches up to size 1.5 were observed in thin snowpack areas inland from White Pass. These avalanches entrained most of the snowpack, pulling pockets of slab in the track. 

Snowpack Summary

A significant storm is impacting the region and has brought 15-30 cm of new snow to the White Pass area with continued snowfall throughout today. The accompanying strong to extreme southerly winds have created extensive wind effect at all elevations, building deep deposits of wind slab in lee areas and generally making for adverse travel conditions and poor snow quality. 

Below the new snow, the snowpack is heavily wind affected. A variety of old surfaces exists including a thin rime crust at treeline and hard old wind slabs at higher elevations. The lower snowpack is facetted above the ground surface.

Terrain and Travel

  • Keep your guard up at lower elevations. Wind slab formation has been extensive.
  • Avoid all avalanche terrain during periods of strong wind.
  • Avoid slopes that sound hollow or drum-like.
  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet
  • If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.

Régions couvertes