JEFFERSON COUNTY, Idaho -

Authorities have released the name of the man missing in the South Fork of the Snake River after an accident Sunday.

Mason Empey, 21, and Torrey Reinhart, 20, both of Idaho Falls, started rafting on the river from the Heise boat launch to fish downstream to the Lorenzo boat dock. About a mile upstream from the Lorenzo dock, Empey tried to retrieve an oar that fell off the raft, which caused him to go overboard, the Jefferson County Sheriff's Office said Monday.

Because the water was moving swiftly, Empey was not able to get back into the raft. The sheriff's office said Empey was not wearing a life jacket.

He was last seen in the water trying to swim to the south bank.

Reinhart steered the raft to the south bank and got help to call 911 around 3:20 p.m.

The search for Empey was called off Sunday due to darkness and resumed Monday morning.

Crews from Jefferson, Bonneville and Madison sheriff's offices, Ammon Police Department and Central Fire Rescue have helped with the search. Jefferson Sheriff Blair Olsen said about three dozen volunteers were working on the search effort Monday.