Boletín de aludes

Vancouver Island

Dec 22 – 23, 2021Avalanche Canada
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Archivado · caducó 5 years ago

Peligro de aludes

Fri
Sat
Alta montaña
4 · Fuerte
Límite del bosque
4 · Fuerte
Bajo el límite
4 · Fuerte
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Lo esencial

10 to 25 cm is inbound Tuesday night with another 10 to 20 cm expected Wednesday, all of it is set to arrive with strong to extreme wind out of the southwest. New slabs may be forming on surface hoar, especially in open areas at mid and lower elevations. Avoid avalanche terrain.

Problemas de aludes

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Very Likely
    Tamaño
    1–2

    We've got 10 to 25 cm coming in Tuesday night and another 10 to 20 cm expected Wednesday, all of it is set to arrive with strong to extreme wind out of the southwest. Here's where it gets sporty, we've got a widespread surface hoar layer in place right now, and it's plausible that in some locations all of this storm snow will come to rest on this persistent weak layer. This would allow the new storm slabs to be pretty sensitive to human triggering Tuesday, and may even allow for some natural avalanches.

Terrain and Travel

  • Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
  • Watch for avalanche hazard to increase throughout the day.
  • Surface hoar distribution is highly variable. Avoid generalizing your observations.

Confidence

Low - Uncertainty is due to extremely variable snowpack conditions reported through the region.

Weather Forecast

Batten down the hatches friends, big wind and plenty of precipitation is headed our way…

TUESDAY NIGHT: Freezing level around 1800 m at sundown, lowering to about 1000 m by day break, 10 to 25 cm of snow at upper elevations and rain down low, strong to extreme southwest wind.

WEDNESDAY: Overcast, freezing level lowering from 1000 m to 500 m throughout the day, strong to extreme southwest wind, 10 to 20 cm of snow up high with rain at lower elevations.

THURSDAY: Broken cloud cover, freezing level around 400 m, moderate to strong northwest wind, no precipitation expected during the day, 2 to 10 cm possible Thursday night.

FRIDAY: Broken cloud cover, freezing level just above sea level, light to moderate southwest wind, no precipitation expected.

Avalanche Summary

No new avalanche observations to report. As new snow and wind come together Tuesday night into Wednesday, we will likely see some avalanche activity in the new storm snow, especially in areas where it stays cold enough for new snow to fall on surface hoar.

Snowpack Summary

Widespread surface hoar has been observed on top of the 20 to 50 cm of premium powder snow that fell last weekend, as evidenced in this MIN, and this MIN from our field team. During that storm, higher snow totals accumulated in the southwest of the region. Temperatures warmed slightly at upper elevations on December 21st, Upper Cruikshank reported +2 C at 1348 m Tuesday afternoon.

A gradual temperature rise may have formed a crust layer within the storm snow in areas below 1000 m in the northern half of the region and closer to 1200 m in the southern half. 

Below a meter of snow from mid-December storms, two crust layers can be found that formed in early December. Small facets (sugary snow) had been reported near these crusts that are likely trending unreactive. Below these crust layers, the snowpack is generally well-settled. Early season hazards such as rocks, stumps, and open creeks remain at lower elevations.

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