PORT HURON, Mich. -- The U.S. Coast Guard has resumed its search for a 19-year-old man who disappeared in the St. Clair River during the annual Float Down event.

Petty Officer Christopher Yaw said Monday the search for Brady Morton is back underway. The Fenton resident was with a group of people who were taking part in Sunday's event.

The Coast Guard says people who were with Morton couldn't say when they last saw him. A Coast Guard helicopter and boats from several agencies are involved in the search.

The St. Clair County sheriff's dive team is using sonar to search for Morton.

People in tubes and rafts entered the U.S.-Canada border river Sunday at Lighthouse Beach in Port Huron, about 55 miles northeast of Detroit. They exited at Chrysler Beach in Marysville.