Dam failure
In 1990, the Bureau of Reclamation prepared a study of a Glen Canyon Dam failure. They predicted that if Lake Powell were at high pool, about of water would surge out of Lake Powell at an initial depth of over . Downstream communities and possibly every dam along the river, including Hoover Dam forming Lake Mead, Davis Dam forming Lake Mohave, Parker Dam forming Lake Havasu, Palo Verde Dam, and other dams and reservoirs, as well as riverside lowlands, would be inundated or severely damaged. The resulting flood would scour the bottom few hundred feet of the Grand Canyon.