Whumpfing and Test Slope Failure on Brockway

We toured on low-angle terrain on Brockway Summit looking for good snow and less avalanche potential. The snowpack here was more shallow than in other areas around the forecast area. Probing around we found depths ranging from 20 cm to 1 m with most places being about 70 cm. It was easy to feel the hollow weak snow in the bottom third of the snowpack (Dec. 11th facets) when we pushed our poles into the snow. In areas without previous tracks, we triggered 5-7 large whumpfs. The snowpack would visibly drop as the weak layer collapsed. These collapses radiated up to 20 m away from where we triggered them. We did an ECT at one of the whumpfs and got an unstable result (ECTP25 on the Dec 11 facets right below a crust). In this area, the facets were about 40 cm below the surface.  Near one of the whumpfs we found a small steep slope. When we jumped on it, it cracked and failed on the facet layer (see photo).