Vicksburg, Mississippi (CNN) -- Storms were forecast Saturday for areas already suffering from the swollen Mississippi River, as Mississippi's governor urged caution.
The rain comes as the Mississippi River was cresting in Natchez, Mississippi. The water was cresting at 61.8 feet, or 13.8 feet above flood stage there, according to the National Weather Service.
There were some early signs of recovery farther north in Vicksburg, where the river had already crested, though the floodwaters are expected to remain for weeks. The Yazoo backwater levee near Vicksburg had hit its peak, CNN affiliate WLBT reported.
"These levees are going to be more and more saturated every day. There will be continuing wave action up against them and so people shouldn't drop their guard," Gov. Haley Barbour told reporters in Yazoo City Friday.
Although many displaced residents in Vicksburg are eager to return to their homes, until the water level recedes, only emergency officials will be allowed, WLBT reported.
"It is illegal to drive a boat in flooded areas and it will remain so until that executive order is lifted, which won't be soon," Barbour said.
The governor also warned of health risks to both the emergency responders and residents.
"We've had reports of water samples where the E. coli level was 200 times normal. This stuff is nasty," Barbour said. The governor himself owns a lake home that has been flooded.
The Mississippi River is not expected to return to its 43-foot flood stage in Vicksburg until after June 14, which is 46 days after it climbed out of its banks, said Amanda Roberts, a National Weather Service hydrologist. It crested at 57.1 feet Thursday. The river is more than a foot over the record set in the city in 1927.
"We're in need of, first off, a place to live. And then second off, pretty much everything you would need in a home," evacuee Pat Wilsoe told CNN affiliate WAPT.
Vicksburg resident Hoover Youenger told the station his home had several feet of water in it.
"In a way, it feels like a big loss, but with Mother Nature you can't do anything about it," he said, WAPT reported.
Severe storms are likely Saturday and Sunday in the Mississippi River, Ohio River and Tennessee River valleys.
Up to 3 inches of rain per hour are possible, with heavier storms on Sunday. The rain could lead to secondary crests and higher crests along the Mississippi from Memphis, Tennessee, southward, CNN meteorologist Sean Morris said.
Some greeted the cresting floodwaters -- which have damaged hundreds of homes and displaced 2,000 Vicksburg residents -- with relief. Others just went to work.
Rusty Larsen, owner of Rusty's River Front Grill in Vicksburg, told CNN affiliate WJTV that his business has picked up some with the floods.
"We stay busy most days anyway, but there's been a lot of people downtown," he said. "I see a lot of local people. Some of them are tourists. Everybody wants to come see the water."
Local officials caution that some area residents may have to wait to return to their homes.
Flooded houses pose a variety of dangers, they said. Rising floodwaters bring debris, hazardous waste and gas leaks, and force snakes or other potentially dangerous animals from their habitats and into residential areas.
"Right now we're moving to the recovery stage," Vicksburg Mayor Paul Winfield told CNN.
"Our first priority, I believe, should be public safety, to continue to encourage our residents and onlookers to stay free of the water."
Law enforcement officials are patrolling evacuated areas to help ensure that abandoned homes and businesses aren't burglarized, Winfield said. And each flooded property must be assessed before an owner can return to it, he said.
Warren County, which includes Vicksburg, has "several hundred homes that have water" and about 2,000 residents have been displaced, Sheriff Martin Pace said.
County residents are accustomed to flooding and know what to do, but none have experienced it at this magnitude, according to Pace.
A slide was detected on the mainline Mississippi levee at Lake Albemarle, the Corps of Engineers said Thursday. That occurs when the integrity of a levee is undermined because dirt and sand are being eroded, spokeswoman Eileen Williamson said.
Crews are working around the clock to help fill the gaps.
If the levee fails, thousands of homes and more than one million acres would be flooded, according to Peter Nimrod, the Mississippi Levee Board's chief engineer.
"So it's very important we hold this levee together," he said.
Farther south, where the Mississippi River has not yet crested, residents were working to clear out their homes and find ways to get by.
Louisiana Gov. Bobby Jindal has asked for federal assistance in grappling with flooding stemming from the Morganza Spillway, where 17 bays have been opened in hopes of sparing New Orleans farther downstream.
So far, the Louisiana Department of Transportation and Development has delivered nearly 150,000 sandbags, 30,000 cubic yards of sand and 33,000 linear feet of fabric-lined baskets, the governor's office said. Approximately 1,150 Louisiana National Guard members have been mobilized.
Mandatory evacuations were in effect Saturday in Happy Town and the Sherburne Wildlife Management Area, the St. Martin Parish Sheriff's Office said. Officials will decide whether evacuations are needed in Butte La Rose on Monday.
Spillway gates are likely to be open for weeks, meaning it will be some time before the river falls below flood stage, allowing evacuees to return.
The flood is the most significant to hit the lower Mississippi River valley since at least 1937. It has affected nine states so far: Missouri, Illinois, Kentucky, Tennessee, Ohio, Indiana, Arkansas, Louisiana and Mississippi.
CNN's Brian Todd contributed to this report.