Strong northeast winds have formed wind slabs on atypical slopes. Sunny skies and a warming trend could start to weaken sun-exposed slopes and cornices.
Strong easterly winds have drifted the new 10-20 cm of snow into wind slabs on lee terrain features. This wind direction is atypical, so you may find wind slabs in terrain features that don't typically have them.
Rapidly rising temperatures and intense solar radiation may initiate wet loose avalanches and weaken cornices. This activity is likely to be most prominent on steep slopes that receive direct day-time solar radiation (slopes that face south through west). Minimize exposure to steep, sun-exposed slopes and cornices on Sunday.
Weak snow at the bottom of the snowpack hasn't gone away. Evidence of deep persistent slab avalanches has been focused in the Sparwood-Elkford area over the past month. Human triggering is most likely around steep rocky terrain features, or anywhere the snowpack is thin and weak. Cornices have grown large and loom over many ridge lines, a failing cornice could initiate a deep persistent slab when it impacts the slope below.
Saturday night: Decreasing cloud, light northeast winds, alpine temperature-25 C.
Sunday: Mix of sun and cloud, light northeast winds, alpine high temperature -8 C.
Monday: Mostly clear, light variable winds, alpine high temperature -1 C, freezing level 1300 m.
Tuesday: Mostly clear, light northeast winds, alpine high temperature 0 C, freezing level 1800 m.
Numerous small (size 1-1.5) wind slabs were reported on Saturday failing both naturally and from human and explosive triggers.
In the aftermath of the previous storm, there were reports of large (size 2-2.5) explosive-triggered avalanches releasing 20-30 cm deep. In a few cases in the neighbouring Lizard Range and Flathead region, these avalanches were triggered by cornice falls.Cornices have grown large with the recent weather, and a cornice failure could trigger a large slab avalanche on the slope below.
Snowfall totals varied across the region, with some areas accumulating 10-20 cm of snow. Strong easterly winds drifted the new snow into wind slabs on lee terrain features in a reverse-loading pattern.
A total of 25 to 45 cm of snow from the previous storm has been redistributed by wind or is well-settled. This snow sits on older wind slabs in exposed areas, and a sun crust on solar aspects (south through west facing slopes). Melt-freeze crusts extend up to about 1900 m on other aspects.
A thick crust/facet layer currently sits 40-80 cm below the surface and can be found up to 2100 m. The middle of the snowpack is generally strong, but the base of the snowpack contains basal facets that are most prominent in shallow rocky start zones.
