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Avalanche Forecast

Archived

Dec 19th, 2023–Dec 20th, 2023

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

Regions

Kitimat, Nass, Rupert, Seven Sisters, Shames, Howson.

Continued light snowfall and wind will promote wind slab formation at upper elevations. Treat open terrain at treeline and below with caution due to the presence of a persistent slab.

Confidence

Moderate

Avalanche Summary

There are no new avalanches to report in the past few days.

Snowpack Summary

Recent new snow has been redistributed by predominantly southwest winds.

A buried layer of weak, feathery surface hoar crystals buried mid-December can be found down 25 to 50 cm from the surface. An additional layer of buried surface hoar may exist deeper in the snowpack, roughly 55 to 95 cm below the surface.

The remaining mid and lower snowpack contains several crusts from early in the season that are generally well-bonded to the surrounding snowpack.

Snow depth decreases significantly at lower elevations.

Weather Summary

Tuesday Night

Cloudy with a trace of snow, ridgetop wind southwest 15 to 30 km/h, treeline temperature -3 °C.

Wednesday

Cloudy with 2-7 cm of snow, ridgetop wind southwest 30-50 km/h, treeline temperature -2 °C.

Thursday

Cloudy with 10 to 20 cm of snow, ridgetop wind south 30-60 km/h, treeline temperature -2 °C.

Friday

Cloudy with 5 to 15 cm of snow, ridgetop wind south 20-50 km/h, treeline temperature -4 °C.

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.
  • Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
  • Surface hoar distribution is highly variable. Avoid generalizing your observations.

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.