Skied a few laps from Peaks 3 to 3.5. While skiing instability was limited to moderately fast moving sloughs of the storms snow in steep terrain on a hard bed surface. While skinning back up the south side of Peak 3 we experienced several large whompfs whenever we deviated out of the center of the gully. For the largest of these, the slab moved a couple inches down hill before arresting. The crack initiated about 20 feet above us and propagated approximately 200 feet across the slope. There were 8 ski tracks in the gully at this point (as shown in attached picture), although the tracks were in the heart of the gully as opposed to out on the thinner part of the slab where we were skinning. Upon inspection of the crack, the failure was 12 inches down at the interface of a 6 inch think hard slab above facets sitting on the ground.