Search and rescue efforts were still under way in Louisville, Mississippi, according to the Mississippi Emergency Management Agency.
Meanwhile, the storm that walloped Mississippi and Alabama overnight was making its way through parts of Florida, Georgia and the Carolinas, according to the Storm Prediction Centre.
Monday's storms left a trail of damage through several Mississippi and Alabama communities.
Mississippi authorities confirmed 12 deaths. Three people died in Alabama and two in Tennessee, according to officials.
In Tupelo, birthplace of Elvis Presley, buildings near a major commercial district on the city's north side were "wiped away," CNN reported citing a local journalist.
In Jefferson County, Alabama-site of the state's largest city, Birmingham, about 90,000 homes and businesses were without electricity Tuesday afternoon, according to Alabama Emergency Management Agency.
About 10,000 customers remained without power around Jackson, Mississippi.