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Avalanche Forecast

Archived

Dec 20th, 2022–Dec 21st, 2022

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

Regions

Sea To Sky, Brandywine, Garibaldi, Homathko, Powell River, Spearhead, Tantalus, Sasquatch, Tetrahedron.

While pushing into bigger terrain assess for wind drifts and firm wind slabs. Small avalanches have the potential to step down to deeper instabilities in large, steep terrain features.

Confidence

High

Avalanche Summary

A size 1 wind slab, that was ski cut in a wind exposed terrain feature was reported on Monday. Otherwise no new reports over the last few days.

If you head out into the mountains, please share your photos or observations on the Mountain Information Network. Your information helps us understand local conditions!

Snowpack Summary

Up to 10cm of recent, low-density snow continues to facet with cold temperatures. Surface snow is cold, light, and ideal to be redistributed by wind into drifts and stiff wind slabs. The new snow overlays an upper snowpack generally made up of old, settled wind-affected snow and a crust on solar aspects.

A number of buried weak layers deeper in the snowpack remain a concern, despite the lack of recent avalanche activity.

Total snow depths remain low for December with roughly 90 to 140 cm at treeline and up to 200 cm in the alpine.

Weather Summary

Tuesday night

Clearing, with isolated flurries. Temperatures around -25 C and light Northeast winds in the alpine.

Wednesday

Sunny, and no precipitation. Temperatures -15 to -25 C and light Northeast winds.

Thursday

Sunny with periods of cloud, and no precipitation. Temperatures -15 to -25 C and light Northeast winds.

Friday

Cloudy with snow, up to 20 cm. Temperatures of -5 to -10 C, and moderate Southwest winds.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

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.