Montgomery County Sheriff's Detective Dennis Herrelson said four boats on Badin Lake that had been near the Tuckertown dam were accounted for and no one was missing.
It takes about a minute for the spillway to completely open oncethe water starts out of the floodgate, Herrelson said.
"They had 60 seconds and they used it, evidently," he said, adding that the boats were banged up but safe.
Montgomery County deputies say there was no warning around 1 a.m. Friday when the dam opened unexpectedly.
A witness initially said two boats were missing. The witness wasin a different boat that made it out of the water and called 911. At the time, Montgomery County Emergency Services Director Ron Adams said two to four people were believed to be missing.
Authorities say the boaters were fishing in a restricted area that was markedwith warning buoys near the base of the dam. The dam separates High Rock Lake and Badin Lake in the centralPiedmont of North Carolina.
Officials say the floodgates are operated remotely and there is no one at thedam to scan for boaters before the floodgates open.
Adams said the volume of water that comes through the spillway hassuch force that it could have pushed the boats to the bottom of thelake.
"It's a sudden discharge of water," Adams said. "Thefloodgates don't open instantly, but they open quickly enoughthat if you're in the way you get hammered."
Montgomery County and Stanly County authorities searched for the missing boaters for three to four hours, but to no avail. They resumed their search 7 a.m. Friday with the help of a Highway Patrol helicopter.
The search of Badin Lake was called off at about 10:15 a.m. when the boaters were found.
The dam is operated by Yadkin Inc., a subsidiary of Alcoa Inc. Officials are investigating the incident.