Authorities in Utah say the death toll is now up to a dozen after flash floods along the Utah-Arizona border Monday engulfed two vehicles carrying 16 people, and swept them into a waterway that is normally dry.
One person from those vehicles remains missing.
"This is one of the worst weather-related disasters in the history of the state of Utah and because of that we are bringing the full resources of the state to bear," said Spencer Cox, the state's lieutenant governor.
Updated at 10:35 p.m. ET: fourth hiker's body recovered