US officials say one person was killed after a tornado swept through North Texas.
A 73-year-old woman died on Monday night in the community of Sherwood Shores, Texas, about 90 miles north of Dallas and near the state’s border with Oklahoma.
Ten other injuries have been reported in Grayson County from the storms.
The same storm system was poised to move into Louisiana and Mississippi on Tuesday, carrying the risk of more dangerous tornadoes and powerful winds.
In Texas, several tornadoes were reported Monday along the Interstate 35 corridor, particularly in the Austin suburbs of Round Rock and Elgin, and close to Dallas-Fort Worth.
Two unconfirmed tornadoes caused damage in the Lake Texoma area of northern Texas and southern Oklahoma.
More than a dozen injuries have been reported in Texas, including the 10 in Grayson County.
By Tuesday morning, the system was bringing heavy rainfall and thunderstorms to parts of Texas and Arkansas, according to Jeremy Grams, lead forecaster with the Storm Prediction Centre, in Norman, Oklahoma.
A tornado watch was in effect for parts of Texas and Louisiana.
In Louisiana, high water early on Tuesday posed a threat to motorists on several roads, including a stretch of Interstate 20 and several state highways after rains overnight, authorities said.
Deputies in Caddo Parish, which includes Shreveport, rescued three drivers from high waters during the night, the sheriff’s office tweeted before dawn.
The storms were expected to intensify throughout the day as temperatures rise, increasing the threat of tornadoes, hail and strong winds.
Much of Louisiana and Mississippi were at a moderate risk of severe weather on Tuesday, the second-highest risk category issued by the Storm Prediction Centre.
Baton Rouge, Louisiana, and Jackson, Mississippi, were among the cities at risk of bad weather on Tuesday.
“We’re still a bit uncertain on just how intense and how longer-lived some of these tornadoes may be, so we’re going to be just below that threshold of the greatest risk,” Mr Grams said.
Forecasters were predicting intense tornadoes and widespread damaging winds, some hurricane-force with speeds of 75mph or greater, in much of Mississippi, southern and eastern Louisiana, and western Alabama.
Louisiana’s federal and state authorities reminded thousands of hurricane survivors living in government-provided mobile homes and recreational vehicle trailers to have an evacuation plan because the structures might not withstand the expected weather.
More than 8,000 households live in such temporary quarters, officials said.
The storm already left misery in its wake in Texas. Damage to homes and businesses occurred in at least a dozen Texas counties, according to reports submitted to the Storm Prediction Centre.
Officials reported damage throughout Jacksboro, about 60 miles north-west of Fort Worth.
There, photographs posted on social media showed a storm had ripped the wall and roof from parts of Jacksboro High School, especially its gym.
“It brought tears to my eyes,” school principal Starla Sanders told WFAA-TV in Dallas.
Thirty miles north-east of Jacksboro, near Bowie, the damage was widespread. Four people suffered minor injuries, said emergency manager Kelly McNabb.