Was standing at the bottom of chair 8 just after 7am. Heard a large boom but knew that avalanche control had not started yet. Looked towards shuksan and saw the slide happening. I could see the slab moving as one piece before cascading off the cliff and running to the valley floor. Very cool impressive. Hard to guess dimensions from that distance but maybe 500’ wide and up to 4 or 5 feet deep in spots.