Avalanche on Black Prince

Did four laps of a treeline ridge near Black Prince. NE aspect. Skied 2150-1850m elevation. Snow was consistently soft deep powder. Witnessed a large (3 or 3.5?) avalanche across the valley on Mount Black Prince. I think (hope) it was remote triggered by a group above and propagated from there. Anyone with more information on this slide please share.

Propagation can be seen from the start zone on the looker's left gully across the tree band and further up slope looker's right.