Kootenay Boundary

A Special Public Avalanche Warning is in effect as large, destructive avalanches continue to fail throughout the region. Don't over-think the current avalanche scenario. Stick to extremely low angle terrain and avoid any overhead hazards.

Moderate -

Friday: 3-7cm of the new snow / Light to moderate westerly winds / Freezing level at 700mSaturday: Mix of sun and cloud / Light westerly winds / Freezing level at 800mSunday: Mostly clear skies / Light southwest winds / Inversion with valley temperatures hovering around freezing and alpine temperatures reaching 2600m

On Tuesday a widespread natural avalanche cycle to size 2.5 was reported from all aspects and elevations as the upper snowpack adjusted to a new load and increasingly warm temperatures.On Wednesday control work around Kootenay Pass produced very large avalanches to size 3.5 on southwest, south and southeast aspects. Natural avalanches ran to size 2.5 on southeast, east and northeast aspects. These avalanches may have started as storm slabs, but quickly stepped down to the mid-December and/or late November weak layers. An awesome MIN post from the same day also details some spooky skier-triggered avalanche activity around treeline in the Nelson area. Click here for details. At the time of publishing this bulletin, no new avalanche activity had been reported, but I don't expect conditions to have improved to any significant extent.Looking forward, natural avalanche activity may taper-off somewhat; however, human triggering of large, destructive persistent slab avalanches at all elevation bands is expected to continue for the foreseeable future in many parts of the region.

40 to 80 cm of recent snow is settling into a cohesive slab on top of the reactive January 5th interface which consists of a crust/surface hoar combination on steep southerly aspects and pure surface hoar on remaining aspects. The late December surface hoar also remains reactive and is now down 50 to 95 cm below the surface. Adding to the complexity of the mid to upper snowpack is the mid-December surface hoar which is now 60 to 130 cm below the surface. This spooky interface continues to produce sudden snowpack test results and is most pronounced at treeline, but is also present below treeline. The overlying slab is now deep, dense and destructive. Two laminated crusts created by rain events in late November lay just below the mid-December interface, and may co-exist with facets. In shallow, rocky terrain the mid-December surface hoar and the late November crust seem to be reacting together which is a volatile combination.