Photos shared on social media showed plants and other items thrown around the parking lot of a Walmart store in Guntersville, Alabama. Nearby stores had to close because of power outages.
High winds left trees tilted sideways and utility lines drooped toward the ground. Farm buildings and homes were damaged in rural Blount County, Alabama, where at least one person was reported injured.
The weather service said two twisters that spun out of the same storm system appeared responsible for the damage. An EF-1 tornado with winds of as much as 90 mph (145 kph) hit Blount County, and the EF-1 tornado that struck Guntersville was a little stronger with winds up to 100 mph.
Schools in DeKalb County, Alabama, and Northeast Alabama Community College delayed the start of classes due to the threat of severe weather. The weather service said several rounds of severe weather could move through the region.
It was the third day in a row of heavy storms for parts of the South.
A storm that meteorologists identified as a tornado with winds of as high as 110 mph (177 kph) destroyed a mobile home in Centreville in the southwest corner of Mississippi. Wilkinson County Emergency Management Director Mattie Powell told WLBT-TV that four family members lost their possessions but were uninjured. Weather may also have contributed to a traffic fatality Saturday near Ruleville, Mississippi.
In Louisiana, the weather service will determine whether a twister was responsible for damage to at least five homes plus cars and boats in the St. Amant community southeast of Baton Rouge on Sunday night. In northeastern Louisiana, Grambling State University and Morehouse Parish schools were closed Monday because of flash flooding.
Louisiana State Police said they were investigating whether heavy rain contributed to the death of a man killed when his car ran off a road and struck an abandoned house during a downpour on Sunday night. Troopers identified the victim as Daniel Brown, 22, of Reserve.