ATLANTA -- Parts of the U.S. Midwest and South braced for more flooding and possible tornadoes Monday following a weekend of deadly torrents and powerful winds that claimed at least 15 lives.

Storms rolled eastward in a band stretching from Alabama into the Ohio River valley on Monday, leaving isolated pockets of damage in their wake.

Heavy rain caused the roof of a furniture store in northern Oklahoma to collapse early Monday, although no one was injured, and parts of the state remained under flood and flash flood warnings after excessive rainfall over the weekend.

The Illinois River that snakes through eastern Oklahoma crested Sunday night at about 29 feet -- well above major flood stage of 18 feet. The Mississippi River was pushing 16 1/2 feet above flood stage in Missouri's Cape Girardeau on Monday, a half-foot shy of the all-time record.

Levees were straining to contain the floods in Missouri. A Cuivre River levee was topped near the town of Old Monroe, and in the St. Louis suburb of Valley Park, residents living below a levee on the rising Meramec River were ordered to evacuate Monday. Interstate 44 was flooded in spots and closed over a 57-mile stretch. Flooding also closed roads in hundreds of other places around Missouri.

More severe weather was expected in the South. A wind advisory was in effect in northwest Mississippi. Tornado warnings were issued for parts of southeastern Alabama and central Georgia Monday morning by the National Weather Service, which advised residents there to take cover. A severe thunderstorm over Fort Benning in Georgia could develop into a twister, the weather service said.

Parts of the Florida Panhandle could be affected by severe thunderstorms or high winds and dangerous rip currents.

The confirmed death toll rose to 15:

-- Flooding and winds killed five people in Arkansas, including a fire chief struck by a vehicle while working the storm. That toll could rise, with authorities searching for two children who were swept away when their mother drove their truck onto a bridge built for low water.

-- Tornadoes hit several small towns in East Texas, killing four people.

-- Three deaths were reported in Missouri, including a 78-year-old man who went out to look at the floodwaters, slipped into a creek and was carried away, and two people who drowned after rushing water swept away cars. One man couldn't save his 72-year-old wife from floodwaters that swept away their vehicle Saturday. Her body was found when the water receded, the Missouri State Highway Patrol said.

-- Two died in Mississippi: a 7-year-old boy electrocuted after unplugging an electric golf cart and dropping the cord in a puddle, and a man killed when a tree fell onto his house, knocking a beam into his head.

-- In Tennessee, a 2-year-old girl died after being struck by a soccer goal post thrown by heavy winds that also knocked down trees and power lines Sunday. Wind and flood advisories remained in effect for much of the state Monday.

In Texas, search teams were going door to door Sunday after the tornadoes the day before flattened homes, uprooted trees and flipped several pickup trucks at a Dodge dealership in Canton.

"It is heartbreaking and upsetting to say the least," Canton Mayor Lou Ann Everett said Sunday.

The storms cut a path of destruction 35 miles (56 kilometres) long and 15 miles (24 kilometres) wide in Van Zandt County, Everett said. The largely rural area is about 50 miles (80 kilometres) east of Dallas.

The National Weather Service found evidence of four tornadoes with one twister possibly on the ground for 50 miles (80 kilometres).

The first reports of tornadoes came about 4:45 p.m. Saturday, but emergency crews were hampered by continuing severe weather, said Judge Don Kirkpatrick, the chief executive for Van Zandt County.

"We'd be out there working and get a report of another tornado on the ground," he said.