Partial burial in trees

Uptracking through trees onto more open meadow when snow collapsed and propogated uphill 5m and 10m wide and 20cm slab slid on 38 degree unconsolidated snow slope. Lead skier taken with moving snow down slope approximately 25m where he stopped wrapped around tree with clear face and upper body but both legs buried and trapped. Second skier pushed 2m into tree and was able to extract and proceed to extract 1st skier after digging to release both legs trapped one with ski still on boot. No injuries fortunately. Skiers retreated and observed 2 crowns above on adjacent gullys that weren't present on approach.