While riding the skier's far left chute of coalpit headwall, the first to drop in our group intentionally let loose, via ski cut, a windslab approx 8" deep 40' wide, which ran the course of the chute approx 1000' down on top of a supportable old wind crust. Second to drop I made a critical error in judgement by making a few turns in the soft snow on the flank of the bedsurface of what had just slid. A patch of hangfire wind slab, significantly smaller than the initial slide, let loose around me and carried me to the bottom of the chute.