A solid melt-freeze crust has locked the snowpack in place in most of the region. Wind slab hazards will be more serious at the highest elevations that escaped the recent rain event.
Our new snow at higher elevations has seen extensive wind redistribution as a result of strong to extreme southwest winds. Expect to find increasingly deep and reactive new wind slabs as you gain elevation into the alpine. Danger is low in areas that have a solid melt-freeze crust on the surface.
Sunday night: Clear. Light west winds.
Monday: A mix of sun and cloud with isolated flurries. Calm or light variable winds. Alpine high temperatures around -14.
Tuesday: A mix of sun and cloud. Light to moderate southwest winds, increasing overnight. Alpine high temperatures around -12.
Wednesday: Mainly cloudy with isolated flurries and a trace of new snow. Light to moderate southwest winds, becoming strong at ridgetop. Alpine high temperatures around -8.
Reports from Saturday in the Fernie area describe a widespread natural avalanche cycle affecting the region over Friday night, with a mix of storm slabs, wet slabs, and loose wet avalanches reaching size 3. Daytime observations were limited by weather, but several large (size 2) wet slabs were triggered with explosives in the same area. The natural avalanche cycle likely eased off as temperatures cooled.
Reports from Friday showed explosives control in the Fernie area yielding storm slabs up to size 2 (large). Crown fracture depths ranged from 10-50 cm, giving good evidence of recent wind redistribution.
While natural avalanche is now low in areas where a crust has capped the snowpack, reactive wind slabs are now likely to exist in the highest elevations of the region that saw heavy snowfall instead of rain over the weekend.
Up to 50 cm of recent storm snow combined with strong to extreme southwest winds have likely formed wind slabs in the alpine and exposed tree line areas above about 2000 metres. Below this elevation, a solid new melt-freeze crust now caps the snowpack. In many areas this capping crust may extend to mountaintops.
The bottom 10-20 cm of the snowpack consists of faceted snow and decomposing crusts. This basal layer has not been an active avalanche problem in the region since December and would likely require a sustained warming event before re-emerging as a concern.
