A 52-year-old boater was in a prohibited area of a lock-and-dam system along the Mississippi River in southeastern Minnesota last week when he was sucked into the roiling waters and killed, authorities said.

The incident occurred Friday at lock and dam No. 8, just north of where Minnesota, Iowa and Wisconsin meet, the U.S. Army Corps of Engineers said.

James K. Freeman of Lansing, Iowa, was pitched from his fishing boat and went under the dam’s gates late Friday afternoon, according to the Vernon County Sheriff’s Office in Wisconsin.

Freeman tried to lower his anchor near the Genoa dam’s rollers, but it failed to hold, the Sheriff’s Office said. He was trying to put on his life jacket when the boat capsized, the Sheriff’s Office added. His body was recovered slightly more than an hour later.

“We had a tragic loss-of-life incident this weekend at one of our lock and dams, where a boater entered the restricted area and was pulled into the churning water at the base of the dam,” the St. Paul District of the Corps of Engineers said in a statement. “The hydraulic effect below a dam is incredibly dangerous. With the turned-up water, a high-powered boat would have a tough time escaping this turbulent water.”

Boats are restricted 600 feet upstream of the dam and 150 feet downstream of the dam. These areas are marked with buoys and on the shore or lock walls.