Bulletin d’avalanche

Glacier

Dec 11 – 12, 2023Avalanche Canada
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Archivé · expiré 3 years ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Buried surface hoar at tree line and in the alpine remains susceptible to human triggering where it exists and hasn't already failed.

Good riding can be found in conservative terrain above tree line.

Lower elevation and ski-outs are crusty with frozen chunder, travel with caution.

Problèmes avalancheux

  • Wind Slabs

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

    With plenty of snow available for transport and moderate winds over the weekend expect to find pockets of reactive wind slab at tree line and in the alpine.

  • Persistent Slabs

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

    A buried crust (felt by pole probing) has bridged this problem at lower elevations. Pay careful attention to when this crust disappears (~2100m). If there is no crust, there will be a higher likelihood of triggering the persistent weak layer (Dec 1 surface hoar) buried by 60-80cm of snow.

  • Loose Dry

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

    Expect loose snow avalanches to run in steep terrain. These could gain significant mass once they have the momentum to scrub down to the crust.

Confidence

Moderate

Avalanche Summary

Reports of rider-triggered wind slabs in wind-prone areas in the Asulkan Valley. A large powder cloud was observed below Forever Young during a strong wind event on Saturday afternoon.

On Friday a group remotely triggered a size 2 avalanche in a steep rocky roll from 20m away along the ridge near Balu Pass.

Snowpack Summary

25-45cm of recent snow sits on top of a rain crust up to ~2200m.

Surface hoar is buried down 60-80cm and continues to give 'sudden' results in snowpack tests and whumpfs in untraveled terrain.

The base of the snowpack is facetted at upper elevations.

The height of snow at treeline is ~130cm, which is below average for this time of year, watch out for early-season hazards.

Weather Summary

5cm is forecasted to fall overnight on Sunday. Monday will be cloudy with sunny periods as a ridge of high pressure settles in.

Ridgetop winds will be light from the North to West with an alpine high of -5. There is a chance of a temperature inversion with cooler temps in the valley bottom.

There is a warming trend for the week, with a small amount of snow forecasted for Thursday.

Terrain and Travel Advice

  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Loose avalanches may start small but they can grow and push you into dangerous terrain.
  • Early season avalanches at any elevation have the potential to be particularly dangerous due to obstacles that are exposed or just below the surface.

Régions couvertes