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Avalanche Forecast

Archived

Dec 20th, 2023–Dec 21st, 2023

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

Northwest Coastal, Boundary, Stewart, Ningunsaw, Ningunsaw, Ningunsaw.

There is uncertainty with snowfall amounts on Thursday. Expect avalanche danger to rise through the day as snow accumulates.

Confidence

Moderate

Avalanche Summary

Recent avalanche activity has been reported as a few explosives triggered size 1-2 wind slabs on north and east aspects in the alpine.

Snowpack Summary

Recent new snow has been redistributed by predominantly southwest winds. There may be a newly buried layer of surface hoar about 15-30 cm below the snow surface at treeline and below.

A layer of facets buried at the end of November can be found 100 to 200 cm below the surface. The snowpack depth varies between 150 and 250 cm at treeline.

Weather Summary

Wednesday Night

Cloudy with 5-10 cm of snow, ridgetop wind southwest 20 to 40 km/h, treeline temperature -7 °C.

Thursday

Cloudy with 5-10 cm of snow, ridgetop wind southwest 30-50 km/h, treeline temperature -5 °C.

Friday

Cloudy with 5 to 10 cm of snow, ridgetop wind south 20-40 km/h, treeline temperature -7 °C.

Saturday

Mainly cloudy with flurries, ridgetop wind south 20-40 km/h, treeline temperature -5 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid rock outcroppings, convexities, and anywhere the snowpack is thin and/or variable.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.