Avalanche Forecast
Regions: Bonnington, Kootenay Boundary, Kootenay Pass, Moyie, Norns, Rossland, South Okanagan, St. Mary, Ymir.
The stable weather pattern is having little effect on our buried layers causing them to remain with us for the time being.
Seek out low-angle terrain that has a deep snowpack to find the best and safest riding.
Confidence
Moderate
Avalanche Summary
Sunday's avalanche activity saw size one and size two avalanches. These were from wind slabs and persistent slabs. They were triggered naturally and by skiers, accidentally and with ski cuts.
New weak layers are beginning to develop in the upper snowpack while our buried weak layers still pose a threat Under the right circumstances, riders can trigger these layers. Heavier loads like those created by smaller avalanches will trigger these deeper layers as well.
Snowpack Summary
At higher elevations, wind slabs are beginning to form from west and southwest winds. In sheltered areas surface hoar growth has been reported. The top 30 to 50 cm of snow contains a wide variety of layers that include, crusts, surface hoar, and facets. These layers have not yet produced widespread avalanches however, they are important to keep in mind as they vary with aspect and elevation as they still pose a hazard depending on your terrain choices.
Layers that are presently a concern include a surface hoar layer developed in early January and a melt-freeze crust from late December that is now down approximately 70 cm. These layers have created our persistent slab problem. The deep persistent slab problem stems from a weak layer created in mid-November and it is now buried 100 to 190 cm deep. These layers are a major concern and if triggered they can result in large avalanches.
Thank you for inputting your snowpack observations in the MIN. For more information on the state of the snowpack, click HERE.
Weather Summary
Monday Night
Cloudy, no accumulation, wind northwest 20 km/h, treeline temperatures around -6 C.
Tuesday
Cloudy with some sun, up to 4 cm accumulation in the western portion of the region, wind northwest 20 to 30 km/h, treeline temperatures -6 C freezing level reaching 1000 m.
Wednesday
Mostly sunny, no accumulation, wind northwest 20 to 30 km/h, treeline temperatures -5 C.
Thursday
A mix of sun and cloud, trace accumulation, wind west 35 km/h, treeline temperature -5 to 0 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
Avalanche Problems
Persistent Slabs
A persistent weak layer of surface hoar is buried 50 to 70 cm down. This depth is prime for human triggering. Below treeline this surface hoar may be replaced with a rain crust.
Deeper in the snowpack, near the base, the snowpack is very weak and can be triggered under the right circumstances. Be especially suspicious of shallow, rocky, or cross-loaded areas with variable snow depths.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 3
Wind Slabs
Shifting winds have been acting on 10 to 15 cm of loose snow sitting on a freezing rain or rime crust, likely forming small wind slabs on a wide range of aspects in exposed areas. Southwest winds has and will continue to be the primary factor here.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1 - 1.5