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Avalanche Forecast

Archived

Dec 19th, 2023–Dec 20th, 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.
Below Treeline
Natural avalanches unlikely.

Regions

Grohman, Norns, Ymir, Crawford, St. Mary, Kokanee, Retallack, Valhalla.

A buried surface hoar layer remains the primary concern. As you gain elevation, assess continually the conditions. Check our Forecasters' Blog for more details.

Confidence

Moderate

Avalanche Summary

No recent persistent slab avalanche activity has been reported lately but the weak layer continues to be reactive in snowpack tests. These layers are most likely to be reactive to triggering in shallow snowpack areas at higher elevations.

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

Snowpack Summary

On sheltered locations, 10-20 cm of light snow overlies a layer of surface hoar and a sun crust. A prominent rain crust is found 35 to 65 cm deep. While this crust may be strong enough to cap another preserved layer of large surface hoar crystals in some areas, in other areas the crust is breakable or absent. It may be possible to trigger this weak 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

Tuesday Night

Cloudy with scattered flurries, trace accumulation, alpine wind southwest 30 to 40 km/h, treeline temperature -3° C, freezing level 1500 m.

Wednesday

Cloudy with scattered flurries, trace accumulation, alpine wind southwest 30 to 40 km/h, treeline temperature -2° C, freezing level 1500 m.

Thursday

Cloudy with scattered flurries, trace accumulation, alpine wind southwest 30 to 40 km/h, treeline temperature -2° C, freezing level 1500 m.

Friday

Cloudy with isolated flurries, up to 5 cm, alpine wind southwest 40 to 60 km/h, treeline temperature -2° C, freezing level 1500 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Surface hoar distribution is highly variable. Avoid generalizing your observations.
  • Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
  • 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.