Large and destructive avalanches will remain a concern long after the stormy weather has ended. See this
blog post for additional info: http://bit.ly/1HHQrK2
Summary
Confidence
Fair - Due to the number of field observations
Weather Forecast
A general cooling pattern is expected for the forecast period. On Tuesday, Wednesday and Thursday only trace amounts of new snow are expected each day with the possibility of occasional sunny breaks. Ridgetop winds should remain light to moderate from the northwest with daytime freezing levels hovering at about 1300m
Avalanche Summary
We have not yet heard how avalanche activity panned out in response to the recent storms, due to limited visibility and the challenges of backcountry travel at this time. We have previously had ongoing reports of very large slab avalanches running on the mid-March persistent weak layer. I would be very surprised if this layer has not performed during the recent storm cycle.
Snowpack Summary
This region is dealing with a very serious persistent slab problem that is currently being subjected to significant additional loading by new snow and/or rain. Depending on how much recent snow has fallen, a facet/crust persistent weak layer buried mid-March lies anywhere from 50-150 cm below the surface. This interface has been incredibly volatile recently and remains sensitive to both human and natural triggering, especially where the slab is thinner. Recent compression tests have produced sudden planar failures at this interface. At lower elevations, rain has saturated the snowpack. Layers below the critical mid-March interface are generally considered to be well-settled and strong.
jlammers,
Avalanche Canada
