Summited XTC peak (looker's left of Whale's Back) on Evening Ridge at noon. Heard some whoompfing as we climbed above tree level. Stayed high on a ridge to start descent and away from open face below the peak where we suspected a slab was lurking. Remote triggered slab from the ridge and watched a size 2 run down the open face and hit mature trees below with significant force. Excellent communication and tight route planning kept us safe. Uneventful pow slashing back to the truck.