Collapsing in Republic Creek

We dug a pit on a W/WNW slope at around 9100 ft in the republic creek drainage. CT 18 and ECTN34 (ECTX then we hit it extra hard 4 more times) on the weak layer about 70 cm down. But overall snowpack was upright and it seemed to be settling down more than we thought. But then as we approached the ridge we triggered 5 separate large collapses ("Whumphs"), all on WSW/SW slopes (between 8700 and 9200 ft). Pole probes revealed a light crust about 12 inches down.