Regions
Kootenay Boundary.
It's early in the season but there is more than enough snow for avalanches. New wind slabs are expected on Tuesday. If you are out in the mountains, please post your observations to the Mountain Information Network.
Confidence
Poor - Due to the number of field observations
Weather Forecast
Stormy conditions persist for Tuesday before an Arctic high pressure moves into the region Tuesday night. Another 10-15cm of snowfall is expected by the end of Tuesday with freezing levels around valley bottom. Alpine winds are forecast to be moderate and should shift from SW to NE on Tuesday. On Wednesday, sunny and dry conditions are expected with freezing levels below valley bottom and moderate NE winds in the alpine. Thursday should be much the same with dry, cold, and sunny conditions but alpine winds should be light.
Avalanche Summary
No recent avalanches have been reported. If you are out in the mountains, please send us your observations.
Snowpack Summary
Limited reports from the region suggest that anywhere from 100 to 150cm of snow sits on the ground. There are two crusts and one surface hoar layer in the snowpack that are of potential concern. But be aware as you read this that there is very little data on these layers and you should investigate the snowpack in your local area. The new snowfall will be sitting on a crust that is on or just below the current snow surface. This will likely be the bed surface for any wind slab or storm slab avalanches going forward. A thick crust layer and a layer of surface hoar both potentially sit in the middle of the snowpack but the stability and distribution of these layers throughout the region is not yet known. New loading could increase the reactivity of these layers or smaller avalanche may have the potential to step down. Dig down and test these layers before committing to avalanche terrain. New wind slabs in leeward features may be sensitive to human-triggering for several days. If you're out in the mountains, please send us your reports. Check out the recent conditions video from Whitewater at: https://youtu.be/lmM4gDom1wM
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
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.