Scarred Island on the Mackenzie River, date unknown (pre-1990)
The Mackenzie is the largest river system in Canada and it experiences some of the most dramatic and dynamic breakups, at scales that are absolutely awe inspiring. This photo illustrates just that, showing the scars on an island that resulted when an ice jam pushed over top of it. To give you an idea of the magnitude of the event, those trees still standing on the island are probably 30 feet (10 m) tall or more.
(Photo source, R. (Larry) Gerard, UofA)