Our objective for the day was to ski the South Face of Mt. Brown in GNP. We ascended the summer trail to the lookout, then the ridge to about 8200 ft. Snowpack was, of course, shallow below 6000 ft. Above this, on sheltered north aspects, it was 2-3 feet with no slab. Calm wind all day. Cloudy (obscured skies above 8000 ft.)
We found a representative location for our pit near the top of the couloir but off the ridge that wasn’t too exposed. We conducted two Extended Column Tests. The first test resulted in full propagation 15cm below the surface with 4 taps (ECTP 4) AND full propagation 40 cm below the surface on 19 taps (ECTP 19). This slab failed on facets capping a thick strong (1F) layer which extended to the ground. Our second test results were similar: same layers, full propagation (see video and photo). This was a great example of using stability test results as a tool. We backed off our original objective given these concerning results. While the skiing looked great in the couloir, the test results were too important to ignore. So, this is why we dig: for more information that’s simply not available just by looking around.
