Crystal Rapids, December 1994

"An unusually intense storm began on December 7, 1966, and dumped fourteen inches of rain in a thirty-six hour period along the North Rim. The resulting flood in Crystal's upper drainages obliterated Pueblo sites that had escaped floods for the previous 900 years. Crystal Creek's rampaging water and mud flows pushed the debris fan 200 feet farther into the Colorado, creating an impressive, ulcer-generating spectacle called Crystal Rapid."
--from "A River Runner's Guide To The History Of The Grand Canyon"