Weary residents in the storm ravaged central United States packed their belongings into moving trucks and prayed for levees to hold Friday as swollen rivers swallowed roads, farms and homes.

"When you see the Mississippi River and it's two miles (three kilometers) wide it's sobering," Tennessee Governor Bill Haslam told CNN.

"We have everything from state prisons to nursing homes that could be in danger from the flooding."

Elaine Fuller, 74, had started putting her belongings in the attic when a federal emergency management agent came to her modest brick ranch home in rural Mississippi and told her she had to leave.

"They said I might be able to see the roof," she said as she walked through the now-empty house near the Yazoo River.

Hundreds of people have been driven from their homes by the rising waters as National Guardsmen and civilian volunteers struggle to build temporary levees and lay out sandbags in front of homes and businesses.

"There are records here being broken that go back to 1927," said Pat Slattery, a spokesman for the National Weather Service.

Much of the flooding comes from the same weather system which sparked the deadliest tornado outbreak in the United States since 1925, which claimed the lives of 350 people across the US south.

That massive storm sucked moisture out of the Gulf of Mexico and brought two weeks of heavy rain to the Mississippi and Ohio River valleys before it finally moved out to sea, Slattery told AFP.

Tributaries across the region have also flooded after the ground became saturated and scores of roads have been closed as the rivers breach their banks.

Most unprotected farmland in northwest Tennessee, southeast Missouri, and northeast Arkansas was swamped and the deep waters covering roadways was hampering evacuation efforts, the weather service said.

Police and firefighters knocked on the doors of more than a thousand homes and businesses in Memphis, Tennessee Friday to warn people to pack up their belongings and seek higher ground.

"Anybody that's ever been flooded before is going to be flooded again, that's a given," Steve Schular, a spokesman for Shelby County, told AFP.

"What we're trying to do is insure the safety of the other people so they can get their belongings out and - most importantly - get themselves out."

Inmates, government workers and volunteers have been filling thousands of sandbags to shore up levees and protect key buildings like hospitals in anticipation of a record crest of the Mississippi River on Wednesday.

But the flood threat is not expected to ease for weeks, and the county's emergency management team is straining to manage the response.

"Starting April 4 we've had continual storms that took down trees and left roads blocked," Schular said from the busy operations center.

"Now it looks like we're going to be here for at least another month."

Officials warned residents to be wary of wildlife fleeing the rising waters -- particularly snakes like the cottonmouth water moccasin which are more agressive due to mating season.

One Tennessee florist has been using paddle boats to get to her greenhouse and retrieve plants and flowers slated for delivery for Mother's Day on Sunday.

"If God would just take his pinky finger and do whatever he does and blow the water away, man we're ready," Teresa Nance, who owns Bayless Greenhouse in Millington told WREG news.