MALAD, Idaho (AP) — Officials say a 21-year-old Malad man drowned Friday while floating the Teton River in an inner tube.

Fremont County Sheriff Len Humphries said Cal Willie, a student at Brigham Young University-Idaho, was tubing with 10 other friends when the group encountered a low-head dam in the Wilford area.

Humphries says Willie got caught in the turbulence on the downstream side of the dam and drowned. He said Fremont County Search and Rescue arrived well after Willie had drowned, but the rescue team managed to retrieve two students who were still in the water after trying to rescue Willie.

Willie’s body had not been located as of Monday night.

Officials warn that low-head dams, also called diversion dams, are exceedingly dangerous because the water spilling over the top of the dam creates a hydraulic effect that can trap a person underwater, even if they are wearing a life jacket. Humphries says anyone planning a float trip should be familiar with the stretch of water and research the locations of low-head dams before they embark.