Boletín de aludes

South Coast

Apr 20 – 21, 2021Avalanche Canada
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Archivado · caducó 5 years ago

Peligro de aludes

Thu
Fri
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
3 · Notable
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Lo esencial

Another hot day with no overnight freeze keeps the avalanche danger elevated. Wet slab avalanches are large enough to affect all elevations running full path to the valley. Don't linger in runout zones and steer clear of cornices from above and below. 

Problemas de aludes

  • Cornices

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    2–3

    Cornices are at their largest at this time of year, and become weaker with warm temperatures and solar radiation.

  • Wet Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    2–3.5

    The likelihood of wet slab avalanches increases during prolonged periods of warm temperatures, as the heat penetrates deeper into the snowpack. In the neighboring Sea to Sky Region and South Coast Inland several very large wet slab avalanches have been observed in the last couple of days. These avalanches are dense, destructive, and can run far, reaching otherwise snow-free valley bottoms.

    Wet loose avalanche activity can also be expected on sun-exposed slopes and below treeline. These avalanches are generally smaller than wet slabs but they can gather mass as they travel and reach low elevations.

Confidence

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

Weather Forecast

Wednesday: Sunny with some clouds and light wind. Alpine temperatures near +10 C and freezing levels 3100 m.

Thursday: A mix of sun and cloud. Ridgetop wind light from the northwest. Alpine temperatures near +6 C. Freezing levels 2200 m.

Friday: Mostly cloudy with light precipitation. Ridgetop winds light from the South. Alpine temperatures +3 C and freezing levels 1700 m. 

Avalanche Summary

In the neighboring Sea to Sky region and the South Coast Inland, multiple wet slab avalanches were observed over the weekend and as of Monday, size 2-4. Many of these involved the full depth of the snowpack, running to the valley bottom. We suspect similar activity to have occurred in the South Coast region as well.

With all of this heat and sunshine with next to little overnight crust recovery, I suspect this type of avalanche activity could continue through the forecast period. It's crucial to start early and end your day early as well as avoid solar slopes. Wet slabs can be very large and destructive.

No new avalanche activity reported on Tuesday.

Snowpack Summary

High overnight freezing levels mean that the snow surface remains moist or wet. In places where the surface forms a crust overnight, it should quickly soften during the day with sunshine and warm temperatures. The highest elevation north aspects (above 2200 m) may still hold dry snow.

Cornices are large and looming along ridgelines. Sun and warm temperatures will increase the chances of cornice failures, especially when temperatures remain above zero overnight.

  

Terrain and Travel

  • Avalanche hazard is expected to to increase througout the day, think carefully about your egress.
  • Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Keep in mind that wet avalanches can be destructive due to their high density.
  • Avoid lingering or regrouping in runout zones.

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