Officials at the Grand County Sheriff's Office in eastern Utah say the man was trying to follow six other people through the river and to an island across from the Gold Bar Recreation Area about 5 p.m. Wednesday.
Authorities say the man fell into the river and was swept downstream. Deputies say the group of people on the island tried to rescue him, but didn't find him.
Rescuers searched with boats, divers, and a helicopter on Wednesday, and say they're resuming the search Thursday.
