Boletín de aludes

Vancouver Island

Dec 25 – 26, 2021Avalanche Canada
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Archivado · caducó 5 years ago

Peligro de aludes

Mon
Tue
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil

Lo esencial

Fantastic snow and safest avalanche conditions can be found in low elevation, wind-sheltered terrain. We have uncertainty around a potential weak layer sitting beneath recent snow at upper elevations so if you plan to venture up high, make observations and assess as you go.

Problemas de aludes

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2.5

    Storm slabs are most likely to remain reactive at upper elevations where the recent snow has been wind loaded over a weak layer of preserved surface hoar or where it sits over a freezing rain crust below 1500 m.

Confidence

Moderate - Uncertainty is due to limitations in the field data.

Weather Forecast

Friday night: A trace of new snow. Light to moderate northwest wind shifting southwest. Freezing level dropping to sea level.

Saturday: Mainly cloudy, scattered flurries bringing 2-8 cm of snow. Moderate southwest winds. Treeline high temperatures near -12 C.

Sunday: A mix of sun and cloud. Light northeast wind. Treeline temperatures dropping to -17 C.

Monday: A mix of sun and cloud. Wind increasing to strong northwest. Treeline temperatures around -13 C.

Avalanche Summary

On Thursday, evidence of natural storm slab avalanches size 2-2.5 were observed out of north facing alpine terrain and several natural loose dry avalanches size 1-1.5 were observed in steep treeline terrain.

Snowpack Summary

Recent low density snow has likely been redistributed into atypical cross-loading or reverse-loading patterns by easterly wind at upper elevations. 15-30 cm now sits over a freezing rain crust below 1500 m and above this elevation it may rest on a layer of large surface hoar crystals. Our field team reported easy shears on this layer in their MIN report from during the storm on Wednesday. You can see photos of the surface hoar prior to being buried by the storm in these MIN reports from Elk Mountain on Monday and Mt Kitchener on Tuesday.

A crust-facet sandwich formed in early December can now be found a meter deep. These layers show limited reactivity and are well bridged by strong snowpack layers above them. Below, the snowpack is generally well-settled.

Terrain and Travel

  • Sheltered low elevation terrain will likely offer the best and safest riding today.
  • Be alert to conditions that change with elevation.
  • Closely monitor how the new snow is bonding to the crust.
  • Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.

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