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RegisterDec 29th, 2022–Dec 30th, 2022
Kootenay Boundary, Bonnington, Grohman, Kootenay Pass, Norns, Rossland, South Okanagan, Ymir, Moyie, St. Mary.
Keep it simple for now, patience is required as a warm and wet snowpack needs time to cool and bond. Seek simple terrain to assess the snowpack prior to beginning your journey into more challenging zones.
New snowfall and wind will continue to add weight to a weak snowpack where buried weak layers are primed for human triggering.
Monday, Tuesday and Wednesday has been action packed with many professional operations reporting that a natural avalanche cycle was occurring. Both persistent and storm slab avalanche were reported as large to very large (size 2.5 to 3).
On Wednesday numerous skier remotely triggered, skier controlled and explosives controlled avalanches have been reported from small to very large (size 1 to 2.5). The continued testing with significant results provides evidence that the snowpack continues to be reactive to light traffic such as skiers.
Further evidence of cracking and settling of the warm and moist upper snowpack provided good evidence of the new storm snow instability.
Explosives work conducted on Monday and Tuesday produced some large (size 2) avalanches that gained mass with the available moist snow.
On Sunday. In the alpine numerous remotely trigger very large avalanches (size 2.5) have been reported. These were described as failing on the December 22nd facet interface/ Persistent weak layer on north east aspects with crown depths averaging 40 cm and gaining significant mass and running far, upwards of 400 meters in length.
Read about their decision making after triggering the first avalanche here.
Tuesday and Wednesday storm snow totals of 16 to 20 cm continued to bury a thin melt freeze crust that formed and it can now be found down 40 cm. Wind and storm slabs have accumulated over layers of either facets, surface hoar or a crust. Strong westerly winds have been redistributing snow into wind loaded features in treeline and alpine terrain.
The snowpack is complex with several deeper instabilities that may persist through the season, and sustained past cold temperatures that had continued to facet (weaken) the snowpack. Layers of concern in this snowpack:
A melt freeze buried December 26 that is suspected to be found on all aspects and elevations below 2000 m. This layer can be found down 40 cm.
An early December layer of surface hoar in sheltered areas and a thin sun crust in open south-facing terrain is buried approximately 60-75 cm deep. This layer has recently produced surprising avalanches in upper treeline and lower alpine terrain features.
The most concerning layer buried in mid November is made up of large surface hoar crystals, facets, and a melt-freeze crust and can be found up to 70 to 120 cm deep. This layer has been reactive at treeline between 1700 to 2200 m, on all aspects.
Thursday Night
Cloudy, snowfall very light; 2 to 4 cm. Moderate south wind 30 to 40 km/h. Freezing levels will maintain around 500 m Alpine temperature high of -4°C
Friday
Cloudy, snowfall; light 1 to 5 cm. Moderate southwest winds 20 to 30 km/h. Freezing levels rising mid day to near 700 m. Alpine temperature high of -2°C.
Saturday
Cloudy, snowfall; very light 1 to 2 cm. Moderate northwest winds 30 to 40 km/h. Freezing level rising mid day to 600 m. Alpine high temperatures -2°C.
Sunday
Beginning to clear, snowfall; very light trace amounts possible. Light southwest winds 20 to 30 km/h. Freezing levels 200 m. Alpine temperatures -6°C.
More details can be found in the Mountain Weather Forecast.