Wind slabs continue to be the primary concern throughout the region. In thinner snowpack areas in the southeast, a weakness at the bottom of the snowpack may also be reactive and smaller avalanches have the potential to step down.
Summary
Confidence
Moderate -
Weather Forecast
A frontal system is expected to bring snowfall to the region starting Friday morning. 5-10 cm of snowfall is expected on Friday with another 5-10 cm Friday overnight. Alpine winds are forecast to be light from the southeast and treeline temperatures are expected to be around -8C. On Saturday, lingering flurries are expected. Alpine winds are forecast to remain light but shift to a northeast direction and treeline temperatures are expected to be around -12C. On Sunday, mostly sunny conditions are forecast with light alpine wind and treeline temperatures around -15C.
Avalanche Summary
No new avalanches were observed on Wednesday. In the days prior to that, explosives and human-triggered wind slab avalanches have occurred to size 2. In the southeast corner of the region, a few explosive-triggered avalanches have stepped down to deeper faceted layers producing persistent slab avalanches in the size 2.5-3 range. On Friday, wind slabs are expected to be the primary concern resulting from recent strong to extreme southwest winds. There is a bit of uncertainty regarding how the new snow will bond to old surfaces which formed during last week's cold snap. Due to these potentially persistent weak layers, recently formed wind slabs may remain sensitive to human triggering for some time. In the southeast corner of the region, there is concerns for a deep persistent problem. A weakness at the bottom of the snowpack has produced some large avalanches recently. Human triggering may be possible in thin areas or smaller avalanches have the potential to step down to this layer resulting in full depth avalanches.
Snowpack Summary
Since Sunday night, 15-40cm of new snow has fallen. In exposed terrain, strong to extreme winds have redistributed much of this snow into fresh wind slabs. The new snow buries a variable surface that developed over the last week of cold, dry, and windy conditions. This interface consists of scoured surfaces and wind slabs in wind exposed terrain, widespread faceting of the upper snowpack, and surface hoar up to 20 mm in sheltered areas. In sheltered areas, there may be another layer of surface hoar in the upper snowpack which was buried around December 10. Observations have been limited, however, the reports we've received suggest the mid and lower snowpack are somewhat unconsolidated and faceting exists to varying degrees. Below treeline, the snowpack is very shallow and early season hazards such as stumps, rocks, and open creeks are still a major concern.
rbuhler,
Avalanche Canada
