A boat flipped over in Lake Pueblo State Park in Colorado Sunday night, killing at least one person and leaving one missing, authorities said. Eleven others were rescued.

Colorado Parks and Wildlife said there were five adults and eight juveniles on board. All the juveniles were saved.

A search for the missing adult was being conducted in 80 feet of water that was a brisk 60 degrees, CPW said.

There was no word on what caused the incident.