Really just a sluff, but was big enough to knock skier off his feet and carry him through some trees. Skier carried through trees about 20-30 feet. Skier grabed tree and stopped before steep and somewhat rocky area. Sluff continued for another 250 feet below skier. Total sluff length was 300 feet. One broken ski pole, everthing else ok. Had dug pit before incident and knew the upper 2-4 inches of snow were on a somewhat weak layer, but rest of snowpack was stable. First skier minor sluffing but not significant, second skier was the one who was caught and carried.