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Avalanche Forecast

Archived

Dec 30th, 2023–Dec 31st, 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.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

Kitimat, Nass, Rupert, Seven Sisters, Shames.

Moderate to strong southwest winds have promoted wind slab formation at uppermost elevations where precipitation fell as snow. The freezing level is forecast to gradually drop.

Confidence

Moderate

Avalanche Summary

On Saturday there were reports of widespread wet loose and wet slab avalanches size 1-2 on all aspects These likely happened Friday, Friday night and Saturday.

On Friday a MIN post described seeing several natural avalanches near the Anderson Cabin.

Snowpack Summary

20-50 cm of heavy storm snow or rain soaked snow at upper elevations snow sits on a rain crust formed around Christmas. At upper elevations, strong winds from variable directions have likely built reactive slabs on many aspects in open areas and near ridge crests.Two buried surface hoar layers can still be found in isolated areas, buried 75-100 cm, and 120-200 cm deep. The remaining mid and lower snowpack contains several well-bonded crusts. Snow depths are highly variable depending on elevation, and decrease rapidly below treeline.

Weather Summary

Saturday Night

Cloudy with light rain or snow, accumulation 2-4 cm above 1000 m, southewest wind 20 - 40 km/h, treeline temperature -2 °C, freezing level 900 m.

Sunday

Mostly cloudy, south west wind 15-30 km/h, treeline temperature -4 °C, freezing level dropping to 500 m.

Monday

Mainly cloudy with 2-5 cm of snow, southwest wind 20-40 km/h, treeline temperature -3 °C, freezing level around 500 m.

Tuesday

Cloudy with flurries, southeast wind 15-25 km/h, treeline temperature -2 °C freezing level around 600 m.

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.
  • Give the new snow time to settle and stabilize before pushing into bigger terrain.

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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.