Avalanche Forecast
Regions: Badshot-Battle, Blue River, Central Selkirk, Clemina, Esplanade, Goat, Gold, Jordan, Kokanee, North Columbia, North Monashee, North Selkirk, Premier, Retallack, South Columbia, Valhalla, Whatshan.
The early January weak layer is producing surprising avalanches where wind slabs have formed over it. Seek out sheltered powder and monitor the layer's depth and reactivity as you travel.
Confidence
High
Avalanche Summary
On Saturday and more sporadically through the week, there have been numerous accidentally triggered wind slab avalanches, mostly small, but occasionally up to size 2.5. One of these larger releases was triggered by skiers entering a couloir on the north side of Mt English on Wednesday. The early January surface hoar (occasionally sitting on a thin crust) has frequently been noted as the failure plane in these avalanches.
Snowpack Summary
Light snow and elevated winds Thursday haven't done much to alter wind-affected surfaces in open areas at all elevations. A skiff of new snow may now cover crusts below treeline and on solar aspects or surface hoar on shaded aspects.
In sheltered terrain, 30 to 40 cm of storm snow has been settling on a layer of weak surface hoar crystals that exists into the alpine. The presence of a slab over these grains has been the main factor determining whether it is a problem. Wind slabs formed over it have been reactive.
A crust/facet/surface hoar layer from early December may be found 90 to 160 cm deep. Activity on this layer has tapered, but it is still factoring into professional assessments in the Selkirks north of Kaslo.
Weather Summary
Thursday Night
Cloudy with continuing with scattered flurries bringing less than 5 cm of new snow. 30 to 40 km/h northwest ridgetop wind, easing. Freezing level to valley bottom.
Friday
Mainly cloudy with isolated flurries. 30 km/h northwest ridgetop wind. Treeline temperature falling to -9 °C.
Saturday
Sunny. 20 km/h northwest ridgetop wind. Treeline temperature around -14 °C.
Sunday
Sunny. 30 km/h north ridgetop wind. Treeline high temperature -14 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Seek out sheltered terrain where new snow hasn't been affected by wind.
- Avoid areas where the snow feels stiff and/or slabby.
- Be aware of the potential for remote triggering and large avalanches due to buried surface hoar.
Avalanche Problems
Wind Slabs
Human-triggerable wind slabs exist below ridges and in cross-loaded terrain on a variety of aspects. A layer of surface hoar buried in early January has kept slabs surprisingly reactive, sometimes propagating well above the trigger.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2