Wind slabs continue to be a concern for human triggering, and the persistent weak layer has been active in isolated locations during the past week.
Summary
Confidence
Moderate - The weather pattern is stable on Tuesday
Weather Forecast
Tuesday: mainly sunny, no snowfall, light westerly winds, -5Cat 1550m, Wednesday: mainly sunny, no snowfall, light westerly winds, -8C at 1500m, Thursday, Cloudy with isolated flurries, no significant accumulation, light to moderate westerly winds, freezing level rising to 1500m.
Avalanche Summary
No new avalanche observations over the weekend from this region. On Friday, our field team reported several natural avalanches up to size 3.0 on east aspects that were visible from Crown Mountain in the Elk Valley North area. These avalanches were probably triggered by wind loading or cornice falls. The interesting observation about these slides was that they stepped down in the track or at the fans around 1900 meters elevation and resulted in a larger avalanche than the initial release.
Snowpack Summary
I suspect that a supportive melt-freeze crust has developed below about 1600 meters due to the recent cooling trend. Recent strong to extreme winds have resulted in extensive wind effect in the alpine and at treeline, scouring lee slopes, loading lee features and forming fresh cornices. A persistent weak layer of buried surface hoar can be found buried at variable depths depending on elevation. For example our field team found it down 45 cm at 1850 meters and down 90 cm at 2150 meters in the Crown Mountain area, where compression tests gave hard sudden planar results. A weak crust/facet layer from early-December can typically be found down over 1m. It has become difficult to trigger this layer but it is still reactive in snowpack tests suggesting it remains capable of wide propagations and large destructive avalanches.
esharp,
Avalanche Canada
