Avalanche Forecast

Issued: Jan 2nd, 2023 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Persistent Slabs.

ldreier, Avalanche Canada

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

Buried weak layers can still be triggered by riders. Remain diligent and stick to low-consequence terrain.

Summary

Confidence

Moderate

Avalanche Summary

Numerous avalanches were triggered by explosives on Monday, releasing on the weak layers described in the Snowpack Summary. They all occurred between 2100 and 2200 m, on all aspects, and were mostly between 80 and 150 cm deep. The results show us that these layers are still a concern and if triggered, could produce large avalanches with high a consequence.

Snowpack Summary

Around 30 to 40 cm of snow overlies a hard melt-freeze crust that extends up to 2000 m. Moist snow or a surface crust may be found below treeline and on steep sun-exposed slopes to ridge top.

Buried weak layers continue to show signs of instability. The two prominent layers of concern are a 60 to 80 cm deep layer of surface hoar and a crust on south aspects that was buried in mid-December and an 80 to 150 cm deep layer of surface hoar and facets that was buried in mid-November.

Weather Summary

Monday Night

Clear with no precipitation, 15 km/h southeast wind, light inversion, treeline temperature -4 °C.

Tuesday

Cloudy, trace of new snow, 15 km/h southwest wind, treeline temperature -10 °C.

Wednesday

Mix of sun and cloud, trace of new snow, 15 km/h westerly wind, treeline temperature -8 °C.

Thursday

Cloudy with up to 5 cm new snow, 30-40 km/h south wind, treeline temperature -4 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Choose conservative terrain and watch for clues of instability.
Be mindful that deep instabilities are still present and have produced recent large avalanches.
Remote triggering is a concern, avoid terrain where triggering slopes from below is possible
Back off if you encounter whumpfing, hollow sounds, or shooting cracks.

Problems

Persistent Slabs

Multiple buried weak layers continue to produce large avalanches that propagate across terrain features. The layers are mostly composed of surface hoar and facet layers found between 60 and 150 cm deep. Most activity to date has occurred between 1800 and 2200 m.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Jan 3rd, 2023 4:00PM