Communities south of the dam are under mandatory evacuation orders as the structure has already seen "spilling".
Police said he was last seen going under the water.
Water surged through nearby villages, destroying homes and a school, and carrying residents away.
"We don't eat none of them big ones," Constable Robert Watkins said.
Parts of the Midwest brace for more flooding and heavy rain this week, after storms claimed the lives of at least five people over the weekend.
The bomb cyclone was just the tip of the crazy weather iceberg.
As Winter Storm Grayson barreled up the East Coast Thursday, the bomb cyclone pummeled the Northeast, causing dangerous floods in Boston.
There are over 180 people dead and 160 others missing after tropical storm Tebin hit the Philippines on Friday.
As Houston shows, it's not only America's coastal counties that can experience catastrophic flooding, yet greater public awareness of inland dangers is still needed.
Researchers say data shows enormous floods to be more common than previously thought, posing a great threat to communities near dams in Colorado, California.
Downpour of up to 8 inches of rain caused the Missouri River to flood streets.
Washed-out residents who didn't live in a flood zone also largely didn't carry insurance.
Rebuilding after events like Louisiana's floods will take predictive flood maps, and insurance that actually reflects the increasing risks of climate change.
Three dead and thousands rescued as storms batter the Gulf Coast.
Louisiana declares a state of emergency amid widespread flooding.