At least one person was killed and 19 others were injured after a tornado slammed central Mississippi overnight and destroyed up to 30 structures, the authorities said.
A tornado struck the town of Louin, about 70 miles east of Jackson, around 11:30 p.m. on Sunday, said Eric Carpenter, a meteorologist with the National Weather Service in Jackson.
Mr. Carpenter said that it was possible that multiple tornadoes had hit the area overnight but that survey crews were assessing the damage Monday morning.
There was no information about how the death occurred or the nature of the other victims’ injuries, said Becky Collins, a spokeswoman for South Central Regional Medical Center in Laurel, where some of the victims were taken. The facility is about an hour south of Louin.
The tornado damaged between 20 and 30 structures, according to Randy Johnson, the sheriff in Jasper County, which covers Louin.
“We had some mobile homes totally destroyed. Roofs off houses,” Mr. Johnson said, adding “You know, just what you’d expect out of a strong tornado.”
Most of the people with injuries were in stable condition or had been discharged from the emergency room, she said, adding that more victims might arrive at the hospital later in the morning.
Gov. Tate Reeves of Mississippi said on Twitter that emergency crews were conducting search-and-rescue missions in the region, using drones in “areas where it is impossible to get by vehicle due to downed power lines.”
As of Monday morning, nearly 350,000 customers across the South were without electricity, including more than 35,000 in Mississippi, according to poweroutage.us, which compiles data from utilities.
More than 29 million people, mostly in Texas, Louisiana and Mississippi were under an excessive heat warning.
In the damaged areas, residents — many of whom were without power — also had to endure excessive heat, Mr. Carpenter said, with the heat index near 105 degrees, and even higher in other places.
While people in Mississippi are used to high summer temperatures, during this time of year the heat index is usually somewhere in the 90s, Mr. Carpenter said.
“It’s been really hot,” he said, and with people outside, trying to clean up without power, “the heat is definitely a concern.”
The temperatures are expected to go down to normal in the next couple of days. For now, some severe thunderstorm warnings remain in effect, as well as river flood warnings, because of the high amount of rainfall.
“Normal summer weather is hot anyway, what we’re dealing with now is extra hot,” Mr. Carpenter said.
Video and images of the damage in Louin showed fields destroyed, homes leveled and debris scattered on roads. One video circulating on social media showed emergency responders rescuing people from damaged homes in the middle of the night.
“It’s been a very interesting weather pattern, especially for June,” Mr. Carpenter said. “In this situation, the jet stream is unusually strong over the area and it’s creating a springlike situation.”
Mr. Carpenter said the fronts hitting the central part of the state have been consistent and have brought a barrage of chaotic weather, including flash flooding.
Sunday night’s tornado occurred less than a week after severe storms swept across parts of the South, killing five people across three states.
“We’re reaching the end of this crazy pattern,” Mr. Carpenter said. “What we got last night we’re hoping is the last really significant event we have to contend with.”
Claire Moses contributed reporting.