Grand Canyon's Colorado River runs 277 miles through the canyon from Lees Ferry. Inside it sits Crystal Rapid, rated 8 out of 10 on the canyon's own danger scale. A 1966 flash flood dumped rock into the river there. The park's swiftwater rescue team does not avoid that water. In one drill, they flipped a raft on purpose in Crystal Rapid, then raced the current to right it. They still train in it several times a year.
