The normally-dry Rillito "River" in Tucson, Arizona, USA, when it really is a river, after an intense "monsoon" summer rain in late July 2006. At the peak of this storm, the US Geological Survey recorded a record flow of 30,000 cubic feet per second [~850 cubic meters per second] about 1-1/2 mile [~2.4 km] east of this bridge.
Image Credit: Theodora Petanidou, University of the Aegean, Greece.