Vermillion Crossing Avalanche

Witnessed a skier trigger a size ~1.5 on a steep sparsely trees roll near Vermillion Crossing. Appeared to be a storm slab of variable thickness (perhaps as thick as 50-75cm in places?). Ran ~15m wide and 75m. Skier avoided involvement thanks to a rapid descent. We were not close enough to get an idea of the exact trigger site or other properties.