A bit of new snow combined with sustained winds will keep our wind slab problem alive and well. Even if the rating is still Moderate, stability will be decreasing as new snow accumulates.
Summary
Confidence
Moderate - Timing of incoming weather systems is uncertain on Sunday
Weather Forecast
Sunday: Cloudy with isolated flurries and a trace of new snow. Winds moderate from the south. Alpine temperatures around -9.Monday: Flurries bringing 5-15cm of new snow. Winds moderate gusting to strong from the southwest. Freezing level rising to 1000 metres and alpine temperatures around -5Tuesday: A mix of sun and cloud with isolated flurries and a trace of new snow. Winds light to moderate from the northwest. Freezing level back to valley bottom and alpine temperatures around -15, closer to -9 in the south of the region.
Avalanche Summary
A Size 2 natural cornice fall was observed on Friday in the Bugaboos area. The cornice released from a northeast-facing feature in the alpine and its failure to trigger any slab below might be attributed to recent scouring of snow from that aspect. No other avalanche activity has been reported in the region, but wind slabs may remain reactive to human triggers in specific areas, such as the immediate lee of ridges.
Snowpack Summary
A trace of new snow has covered a layer of surface hoar that was growing on the surface before January 6. Below the surface, recent cold temperatures have been promoting faceting of the upper snowpack. In exposed areas at all elevations, recent winds have scoured windward slopes and formed hard wind slabs in unusual places as the winds shifted from west to northeast. Continued moderate variable winds have been keeping wind slabs fresh and touchy in some areas. The layer of facets and surface hoar that was buried mid-December has been giving hard and broken results or non-results in snowpack tests where it is found around a metre below the surface. Snowpack tests in shallower areas, however, have yielded moderate sudden planar results on this persistent weakness, suggesting the primary concern for persistent slab avalanches is in shallow snowpack areas. With that said, the potential for a wind slab avalanche to step down to this weak layer remains a concern where it lies deeper in the snowpack. The lower snowpack is well bonded and features a thick rain crust near the ground.
cgarritty,
Avalanche Canada
