From Texas to Ohio, authorities are struggling to shut off electricity and gas, while cities are closing roads and distributing sandbags to protect homes and businesses.
In Kentucky, the central part of Frankfort, the state capital, was flooded.
As long as I've lived, and I'm 52 years old, this is the worst I've ever seen, says restaurant owner Wendy Quire.
Since Wednesday, when the bad weather began, 18 deaths have been reported, including ten in Tennessee.
A 9-year-old boy in Kentucky died while trying to get to the school bus, and in the same state, a 74-year-old was found dead in a vehicle that had sunk in the water. A 5-year-old girl died in her home in Little Rock, Arkansas, in a weather-related accident.
In several places, authorities are urging residents not to venture out on the roads unless absolutely necessary. According to forecasts, the floodwater may continue to rise in several areas for several days to come.
During the night to Sunday, several new tornado warnings were issued in Alabama and Mississippi, and flood warnings in several counties in Kentucky, Mississippi, and Tennessee.
Earlier in the week, entire residential areas were destroyed by tornadoes.
