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Avalanche Forecast

Archived

Dec 17th, 2023–Dec 18th, 2023

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

Regions

Kootenay Boundary, Bonnington, Grohman, Kootenay Pass, Norns, Rossland, South Okanagan, Ymir, Crawford, Moyie, St. Mary.

Continue to be wary of a buried layer of surface hoar. Use good travel habits to avoid getting caught off guard.

Read our Forecasters' Blog for details on a persistent slab problem in the region

Confidence

Moderate

Avalanche Summary

On Saturday, explosives control produced a few, size 1, wind slab avalanches on lee terrain features in the alpine.

If you go out in the backcountry, please consider sharing your observations on the Mountain Information Network (MIN).

Snowpack Summary

A dusting of snow has buried a layer of surface hoar and sun crust. A prominent rain crust is found 30 to 60 cm deep. While the dry snow above the crust is bonding well, in some areas below the crust is a layer of large weak surface hoar crystals. It may be possible to trigger this surface hoar layer in areas where the crust is thinner and less supportive, with higher-elevation terrain being the most suspect. Typical snowpack depths at treeline are 70 to 110 cm, and taper rapidly below treeline.

Weather Summary

Sunday Night

Mainly clear with no precipitation, alpine wind west 30 to 50 km/h, treeline temperature 0 °C with a possible temperature inversion.

Monday

Mix of sun and cloud with no precipitation, alpine wind southwest 30 to 40 km/h, treeline temperature 0 °C with a possible temperature inversion.

Tuesday

Cloudy with scattered flurries, 2 to 7 cm accumulation, alpine wind southwest 30 to 50 km/h, treeline temperature -4°C.

Wednesday

Cloudy with isolated flurries, 2 to 5 cm accumulation, alpine wind west 20 to 30 km/h, treeline temperature -3°C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Carefully evaluate bigger terrain features on an individual basis before committing to them.
  • Surface hoar distribution is highly variable. Avoid generalizing your observations.
  • Early season avalanches at any elevation have the potential to be particularly dangerous due to obstacles that are exposed or just below the surface.

Problems

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.