A slide came down from the upper terraces through the second pitch. All climbers were at an anchor or under the protection of a rock ledge. The slide deposited about a foot at the base of Miller's Pillar but was much deeper in the debris field at the mouth of the couloir. Trigger is unknown and unobserved. Assuption of everyone in our party was that it was a wind-loaded slab release. Observation was at 6,000 ft.