Strong winds and incremental snowfall are expected to continue to build wind slabs at upper elevations. In the northern part of the region, buried weak layers require careful evaluation and terrain selection.
Incremental snowfall and strong southwest winds are expected to continue to build reactive wind slabs on lee features at upper elevations. These areas of concern overlap with where cornices may also be reaching their breaking point.
In the north of the region (e.g. Duffey, Hurley, Goldbridge) on sheltered slopes near and above treeline, a layer of surface hoar from February 22 may be buried under 40-70 cm of snow. Recent snow, wind, and solar radiation may have promoted cohesion in the slab above this layer, priming it for human triggering. Travelling near steep, open slopes at upper elevations warrants an investigation of this layer.
Deeper in the snowpack, a weak layer of facets near the ground presents a lingering concern on steep, shallow slopes in the alpine.
Sunday: Cloudy, up to 5 cm of snow, strong southwest winds, freezing level 500 m.
Monday: Mostly cloudy, up to 5 cm of snow, strong southwest winds, freezing level 1300 m.
Tuesday: Mix of sun and cloud, scattered flurries with up to 5 cm of accumulation, strong southwest winds, freezing level rising to 1500 m.
Wednesday: Decreasing cloud, 5-10 cm of snow overnight, strong southwest wind decreasing to light, freezing level 1000 m.
Over the weekend, recent small (size 0.5-1.5) wind slab avalanches were reported breaking 20-30 cm deep on lee features near and above treeline. Periods of strong solar radiation on Saturday initiated pinwheels, rollerballs, and small wet loose avalanches on steep, sunny slopes.
Incremental snowfall and strong winds from the southwest are expected to continue to build reactive wind slabs at upper elevations. 20-30 cm of snow has accumulated since Friday, with 30+cm in the south of the region (i.e. Coquihalla). Strong southwest winds have been redistributing the storm snow into wind slabs on lee features at upper elevations and rapidly loading cornices.
In the northern part of the region (i.e. Duffey/Hurley/Goldbridge), a weak layer of sugary faceted snow and feathery surface hoar from February 22 may be buried 40-70 cm deep and warrants careful evaluation. There is high uncertainty regarding the distribution of this weak layer in the region. However, where it does exist, conditions may be prime for human-triggering. Check out the latest forecaster blog that offers a deeper dive into these conditions.
Also in the northern part of the region (i.e. Duffey/Hurley/Goldbridge), a deep instability exists at the base of the snowpack. It has not produced recent avalanche activity since February 17th. Rapid warming or heavy loading by new snow/wind/rain events have the potential to re-awaken this layer.
