Avalanche Forecast
Regions: Bonnington, Grohman, Kootenay Boundary, Kootenay Pass, Norns, Rossland, Ymir.
Expect to find new windslabs that will remain reactive to rider triggering.
Choose low-consequence terrain and watch for signs of instability.
Confidence
Moderate
Avalanche Summary
On Friday near Nelson as winds began transporting light snow, numerous small (size 1 to 1.5) wind slabs where triggered naturally, via ski cut and a few rider triggered. They occurred on all aspects with the exception of east and near the 2000 m elevation.
On Wednesday 2 large (size 2 to 2.5) persistent slab avalanches where rider triggered, both on a north aspect at approximately 2200 m. One was near Nelson, the other Rossland. Review this MIN report link for further details
Snowpack Summary
In many areas strong winds have stripped and scoured open alpine and treeline features. Approximately 10 to 15 cm of light, dry surface snow has been transported. Windslabs have formed in lee aspect terrain. In sheltered areas, 30 to 50 cm of settling snow remains intact.
Below this recent snow, a thin crust is present below approximately 1600 m. Above 1600 m a layer of surface hoar is present and reactive to testing and rider traffic.
Weak layers of surface hoar or facets and a crust continue to persist in the mid-snowpack and can be found down between 50 and 120 cm.
The lower snowpack is generally strong and well-bonded.
Review this video on State of the snowpack for further details.
Weather Summary
Saturday Night
Cloudy with light snowfall 1 to 5 cm. 15 to 20 km/h southwest ridgetop wind. Treeline temperature -5 °C.
Sunday
Cloudy with light snowfall 1 to 5 cm. 15 to 25 km/h southwest ridgetop wind. Treeline temperature -6 °C.
Monday
Cloudy. 10 to 15 km/h southwest ridgetop wind. Treeline temperature -4 °C.
Tuesday
Cloudy. 5 to 10 km/h south ridgetop wind. Treeline temperature -3 °C.
If you head out in the backcountry, let us know what you are seeing by submitting a MIN report!
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Pay attention to the wind; once it starts to blow, sensitive wind slabs are likely to form.
- Keep in mind that human triggering may persist as natural avalanches taper off.
- Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
Avalanche Problems
Wind Slabs
As winds increase, expect new and sensitive wind slabs to begin to form in lee aspect terrain and cross-loaded areas.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2
Persistent Slabs
The sensitivity of this problem decreases in the southern boundary of this forecast region. Likely areas for triggering this weak layer are thin spots .
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Unlikely - Possible
Expected Size: 1 - 2.5