YELLOWSTONE NATIONAL PARK, Wyo. -

A search is under way for a Georgia man who was swept down the Yellowstone River near Tower Junction on Monday evening.

According to a news release from Yellowstone National Park, three young concession employees used inner tubes to float the Lamar River on Monday.

"Floating the river is prohibited by park regulations due to safety concerns," the park said.

Shortly after reaching the confluence of the Lamar and Yellowstone Rivers, two of the men got out of the water. The third man, 22-year-old Darien Latty, was last seen about 7:30 p.m. Monday being propelled downstream by the rushing water, without an inner tube or life jacket.

He is 5'7", 140 pounds and has brown hair and brown eyes.

Searchers didn't find any sign of Latty on Monday.

The search increased Tuesday, with a helicopter, three dog teams, and several small groups of people searching the Yellowstone River corridor from Tower Junction downstream to Gardiner, Montana. About 50 people were searching for Latty as of mid-afternoon Tuesday.

Anyone with information regarding the whereabouts of Latty is asked to call Yellowstone National Park at (307) 344-2642.