Over the weekend, four people died in Texas, two in Louisiana, one in MS and another in Alabama.
At least four people are dead after 14 tornadoes hit communities from eastern Texas to MS, with the local area "looking like a war zone".
Severe weather had also swept the South on Sunday, unleashing suspected tornadoes and flooding that killed at least eight people, injured dozens and flattened much of a Texas town. There were no immediate reports of any injuries.
The weather says the numbers could go up because teams are still assessing damage.
The Angelina County Sheriff's Office said an 8-year-old and a 3-year-old died when strong winds toppled a tree onto the back of their family's auto in Lufkin while it was in motion. The Stafford County Sheriff's Office said the unidentified woman, 78, had been asleep when the tree fell at 1:43 a.m.
In Mississippi, authorities said there was one storm-related death in Monroe County.
The National Weather Service in Birmingham says that another storm system is expected to move into the Central Alabama area by Thursday morning.
Local emergency management officials say one person is dead after a tornado swept through a northern MS town late Saturday.
Warm air enhanced the atmosphere's instability Saturday, allowing the storm system to rev up more energy and grow, CNN meteorologist Chad Myers said.
Heavy rains and storms continued to rake the Magnolia State into the night, with Mississippi State University's 21,000 students huddling in basements and hallways as a tornado came near the school's campus in Starkville.
"A strip of homes on the other side of town over here are completely gone, just gone, everything is gone", Robertson County Emergency Management Coordinator Billy Huggins told NBC News.
"We were hit really, really, hard".
Tournament organizers have moved up tee times for Sunday because of the storm threat.
While the threat of tornadoes will be lower by then, damaging winds could still bring perilous conditions.