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Avalanche Forecast

Archived

Dec 31st, 2022–Jan 1st, 2023

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

Regions

Lizard-Flathead, South Rockies, Flathead, Lizard, Bull, Elkford East, Elkford West.

Triggering large persistent slab avalanches remains possible.

Confidence

Moderate

Avalanche Summary

A few small to large (size 1 to 2) storm slab avalanches were triggered naturally and by explosives on Friday and Saturday, generally 30 to 60 cm deep within recent storm snow.

Large (size 2 to 3) avalanches occurred within the past week, with some of them stepping down to deeper weak layers. We suspect it is becoming more difficult to trigger these deeper layers, however caution should be taken in challenging or complex terrain given the uncertainty and consequence of large avalanches.

Snowpack Summary

Around 50 cm of snow sits on a hard melt-freeze crust found up to treeline elevations formed by rain on December 26. Moist snow or a surface crust may be found up to around 1600 m.

Two deeper layers of surface hoar and facets could still be triggered in specific terrain. These include a 40 to 80 cm deep layer buried mid-December and an 80 to 150 cm deep layer buried mid-November. These layers are generally deeper in the Lizard Range and Fernie areas and shallower towards Sparwood and Elkford. The layers may be easier to trigger where they are buried within the top 100 cm of the snowpack.

Weather Summary

Saturday Night

Cloudy with light snowfall, accumulation 1 to 3 cm, 20 to 40 km/h west wind, treeline temperature -5 °C.

Sunday

Mix of sun and cloud with no precipitation, 10 km/h west wind, treeline temperature -8 °C.

Monday

Mix of sun and cloud with no precipitation, 10 km/h southwest wind, treeline temperature -6 °C.

Tuesday

Sunny with no precipitation, 10 km/h southwest wind, treeline temperature -6 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Back off if you encounter whumpfing, hollow sounds, or shooting cracks.

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.