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Avalanche Forecast

Archived

Dec 18th, 2023–Dec 19th, 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 weak layer remains a concern in the alpine. 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

No recent persistent slab avalanche activity has been reported 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

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

Monday Night

Mainly cloudy with isolated flurries, 2 cm accumulation, alpine wind southwest 30 to 40 km/h, treeline temperature -1 °C, freezing levels drop to 1300 m.

Tuesday

Cloudy with scattered flurries, 2 to 6 cm accumulation, alpine wind southwest 40 to 50 km/h, treeline temperature -3°C, freezing level 1300 m.

Wednesday

Cloudy with isolated flurries, trace accumulation, alpine wind west 30 to 50 km/h, treeline temperature -2°C, freezing level 1500 m.

Thursday

Mainly cloudy with isolated flurries, trace accumulation, alpine wind west 40 to 50 km/h, treeline temperature -2°C, freezing level 1700 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.