Our party of 3 was skiing together. The 1st skier was able to ski away & avoid the slide. However, the 2nd skier was knocked down & carried approx. 100+ feet before coming to a rest with their skis & legs buried. He was dug out by 3rd skier who was above & skied down to assist. No injuries occurred, however a ski pole was lost in the slide. A second party had previously skied the line just adjacent to where the slide occurred , & heard a distinct collapse just as our party entered the slope. They observed our party just after the slide occurred, & made sure everyone was OK, before exiting the area.
Our party was familiar with area & terrain. We had skied adjacent to the area the previous day with no issues. The specific area historically does experience wind-affected snow, specifically wind scouring, which helps with slab formation.
The sliding surface was the buried rain crust of several weeks ago which is quite hard & will be undoubtedly be a persistent problem. A weak facet layer on top of the crust certainly did not help the situation & bonding is quite tentative at this elevation and aspect. We did not experience any issues at lower elevations or non roll-overs (anything less then 35 degrees) but that was only our experience in this specific area. Bottom line: bad judgment, we should have better assessed the additional probability of wind slab in that area than what we had been skiing the day before. We also underestimated the risk caused by presence of a persistent weak layer overlying a very hard sliding surface.