Avalanche Forecast
Regions: Boundary, East Stikine, Howson, Kitimat, Nass, Ningunsaw, Northwest Coastal, Rupert, Seven Sisters, Shames, Stewart, West Stikine.
Normal cautions should be sufficient to manage lingering wind slab and isolated persistent slab issues. It's not quite open season out there.
Confidence
Moderate
Avalanche Summary
Small rider-triggered wind slabs have continued to figure in reports from the early week, with one new report of a slab failing on the buried surface hoar/facets from early February. This occurred well south of the region but in similar snowpack conditions.
Small, natural wet loose avalanches were also prominent in Monday's reports.
Significantly more natural, rider and explosive-triggered wind slabs and persistent slabs on the same layer were reported last week.
Snowpack Summary
All exposed terrain at treeline and above is highly wind affected by recent strong winds from variable directions.
In sheltered terrain, a new layer of surface hoar is forming on the surface. A sun crust may be found on steep south and west-facing slopes.
An older layer of surface hoar and/or facets may be found buried 20 - 40 cm in sheltered terrain. It is most problematic where wind has added to this depth and contributed to slab formation above the layer.
A crust from late January can be found down 20-50 cm.
Weather Summary
Tuesday night
Mainly clear. 5 - 10 km/h north alpine wind. Freezing level to valley bottom.
Wednesday
Mainly sunny. 5 - 10 km/h northeast alpine wind, easing and shifting northwest. Treeline temperature -1 °C with freezing level to 1100 m. Possible above freezing layer around 1500 m.
Thursday
Mainly sunny with cloud increasing. 20 - 30 km/h southwest alpine wind, increasing. Treeline temperature around 0 °C with freezing levels rising to 1300 m.
Friday
Cloudy with flurries continuing from the overnight period bringing 5-15 total cm of new snow. 60 - 70 km/h southwest alpine winds. Treeline temperature -2 with freezing levels to 900 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Carefully evaluate steep lines for wind slabs.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Avalanche Problems
Persistent Slabs
A weak interface of buried surface hoar and/or facets sitting on hard crust can be found up to 50 cm deep. It has been most problematic on north-facing slopes at upper treeline.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1 - 2
Wind Slabs
Recent strong winds have come from a variety of directions, transporting snow and forming wind slabs on a range of aspects. Most slabs have likely stabilized, but isolated reactive slabs may be found near ridgecrests.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1 - 1.5