Avalanche Forecast

Fair - Due to limited field observations

In the wake of sunday's snowfall, a ridge is expected to dominate the Kootenay-Boundary region bringing clear skies, alpine temperatures of -9.0 and light to moderate northwest winds.On tuesday morning the pattern is expected to persist, but should breakdown in the afternoon as light precipitation, continued colder temperatures and light to moderate northwest winds are expected into wednesday morning.The same wind values are expected to persist into wednesday afternoon; however a ridge is expected to rebuild bringing clearing skies and freezing levels at, or near, surface.

Numerous size 3 natural avalanches were reported north of the region on friday on a suspected early season crust that has been reactive in a few regions throughout the province. At this point we have extremely limited observations from the Kootenay-Boundary region; but the recent weather has been sufficient to produce significant avalanche activity at treeline and in the alpine. If you have any avalanche observations to report, please email us at: forecaster@avalanche.ca.

I have added a bit of information from the Selkirks to the North of this region. We are not getting much information from the Kootenay-Boundary, but I suspect that there is a great deal of variability in this region as well. Take a minute to read about what we know happened in the Selkirks. I would not be surprised to hear of similar things happening in this region. Until we know otherwise lets assume that the recent heavy loading has caused storm slabs and or deep instabilities that can be triggered by humans. Generally we have about 150 cms in the alpine, and treeline has been showing some variability between 50 -150 cms. There are locations in the alpine that have 200 cms plus already. On thursday the wind was strong in the alpine from the east-southeast. We were feeling pretty sure that there was a major avalanche cycle going on in the alpine, that we thought was probably failing on the buried surface hoar layer that has been reported to be down about a metre. On friday we received new information from the Selkirks south of Revelstoke that there was indeed a major avalanche cycle up to size 3.5 during the last storm, but it appears that most of the avalanches were sliding on a layer that is near the ground; perhaps a rain crust from October. The slides may have started on the surface hoar layer and then stepped down to the crust. This crust has also been highly reactive in the Lizard Range to the east. Expect wind slabs at ridge crests and over steep rolls, storm slabs caused by recent snowfall, and until we hear otherwise, I think it would be prudent to assume that the aforementioned crust also exists in the Kootenay-Boundary region and that deep releases are a possibility. We hope to get some more information soon, as operators start getting out into the field. There is cooling pattern expected for monday and there may be a slight improving trend in the snowpack. Having said that, with the limited information that we have the "take home" advice from recent activity is that you should be very suspicious of any slopes in the alpine or at treeline that have not recently avalanched. Due to the variability of the amounts of snow in different drainages, I think that the absence of recent avalanche activity in an area would concern me as well. These are difficult early season conditions to evaluate. I recommend being very conservative with your terrain choices. Let me know what you think! forecaster@avalanche.ca