Video of the incident shows the girl slipping through the safety bar, which briefly held her aloft while she dangled in the air.
The teen struck a tree before landing in the crowd, which had gathered to catch her. She was treated at the park, then taken to an area hospital.
Park officials said the ride was working properly.
"There does not appear to be any malfunction of the ride, but we have closed the attraction until the a thorough review can be completed," USA Today reported park officials said in a statement.
Another person was injured as he was trying to help catch the girl.