Five people died in the storm in the southeastern USA, and at least 13 tornadoes were registered that destroyed houses and felled trees.
In the US states of Alabama and Tennessee, five people were killed, and dozens of people were injured.
The storm also hit parts of Mississippi and Louisiana on Wednesday, the weather service said.
At least five tornadoes were confirmed in Alabama, three in southern Tennessee, one in Louisiana and four in Mississippi.
The storm came shortly after firefighters brought under control fires that killed seven people and damaged or destroyed more than 700 homes and businesses in Tennessee.
In Alabama, more than 50 millimeters of rain fell before the storm in areas that had previously experienced months of drought.
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