The Black Thunder ride opened last August at the Rapids Water Park in Riviera Beach, the Palm Beach Post reported. The ride is described on the park Web site as a "fast ride in the pitch black darkness."

Tina Hatcher, a spokeswoman for the park, said that the ride will remain closed until an investigation determines what caused the accident.

Katie Nadeau, who went down the slide just before the injured family, said that the father and an older boy were knocked out and a younger boy was bleeding. Officials said that the father was hospitalized overnight for observation, two younger children were released after several hours and a teenager was treated and released.

The mother of the children was the first to notice the crash. She was "flipping out," Nadeau said.