Regions
Kootenay Boundary.
The kiss of the sun can spark avalanche activity. Plan your route to avoid exposure to sun-baked slopes.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain
Weather Forecast
A ridge brings mixed sun and cloud for the weekend. The freezing level is around 1700 m. A front is expected to pass through late on Sunday/ Monday morning, bringing light snow with the freezing level around 1400 m.
Avalanche Summary
A handful of size 1-2 storm slabs were triggered by skiers, naturally and with explosives on Thursday. These were almost all on NW-NE aspects and above 1900 m. The kiss of the sun may spark a loose wet avalanche cycle, or make the storm slab more reactive.
Snowpack Summary
Cornices are large and looming in some areas. Recently formed melt freeze/ sun crusts are now buried by storm slabs and variable wind slabs. Several crusts are buried in the upper snowpack. The late February persistent weak layer down 70 to 120 cm remains a lingering concern. Test results are variable, with occasional sudden planar (pop) results. This interface may remain more reactive on northerly (shaded) aspects above about 1700 m, where buried surface hoar has the best chance of preservation. On sunny aspects, this interface may be a crust/ facet layer. While becoming unlikely, it could be triggered by a cornice fall or from a thin snowpack area.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.