Two boys from Helena drowned in the Missouri River Friday evening after their go-kart went off a road and landed in the water three miles south of Townsend.

Broadwater County Sheriff Brenda Ludwig said her department received a call at around 5:20 p.m. Friday reporting that the two boys had gone missing in their go-kart.

Ludwig said 12-year-old Justin Williams and 10-year-old Ethan Ray James Winscott, both of Helena, were friends and had been camping with their families near York Island on the Missouri River since last Thursday.

The accident brings to four the number of people who have died on local rivers over the past seven days. A week ago today, one adult drowned and one went missing on the Dearborn River when their party's raft overturned in high water.

The Missouri River gauging station at Toston, located south of Townsend, showed river flows of 13,600 cubic feet per second, according to the U.S. Geological Survey.

"We located what looked like tracks from the go-kart leading into the river," said Ludwig. "There's a dirt road that parallels the river right there. It was on the embankment there at the river."

Deputies from the Broadwater County began looking for the two boys near the site of the tracks Friday evening. Members of Broadwater County Search and Rescue, along with Lewis and Clark Search and Rescue, a dive team and Montana Fish, Wildlife and Parks, began searching as well, deploying from the bridge at Indian Creek.

"We had people walking the banks from the point last seen and moving downriver," Ludwig said. "The family had people assisting also, and we had local ranchers helping too."

At around 7:49 p.m., Ludwig said searchers located the go-kart roughly 3 miles downriver from where it apparently entered the water. Williams was found in the submerged vehicle.

"We continued searching for the other juvenile," Ludwig said. "We searched as late as we could."

Searchers borrowed thermal-imaging equipment from East Helena and continued searching the riverbanks throughout the night.

Broadwater County lined up additional resources Saturday morning from the Montana Highway Patrol and the Gallatin County Search and Rescue team.

Members of Lewis and Clark Search and Rescue arranged to postpone their ongoing search for Jeff Rayman, the Helena man who is still missing on the Dearborn River, to assist in the search for the missing boy.

But at 7:45 a.m. Saturday, a fisherman located Winscott at the south end of Canyon Ferry Reservoir, roughly nine miles from where the tracks left the road.

"We're still investigating to see why they went off the road," Ludwig said. "Out hearts go out to the family."

Reporter Martin Kidston: 447-4086 or mkidston@helenair.com