Strong winds and torrential rain were expected to pose a serious flood risk across the Southeast on Thursday, part of a severe storm system that spawned tornadoes in Oklahoma and Arkansas, injuring at least 10 people — one of them critically.
Flash-flood warnings were in effect for parts of Mississippi, Tennessee, Louisiana and Arkansas, the National Weather Service said, while flood watches were issued as far as northern Florida, Alabama and Georgia.
Tornado warnings were also in effect for parts of Louisiana and Arkansas as of 4:30 a.m. ET.
"There's severe risk in play from Nashville to Tallahassee," said Kait Parker, a meteorologist for The Weather Channel.
More from NBCNews:
Severe Turbulence Sends 2 on Passenger Jet to Hospital
Woman Trades @DietDrPepper for $5K Water Donation to Flint
State Department Apologizes for Calling Americans Ugly
The National Weather Service confirmed that a tornado touched down Wednesday evening in north Tulsa. Oklahoma. NBC station KJRH reported that trees were downed, some structures were damaged and several roads were closed.
The state Emergency Medical Services Authority said nine people had been taken to hospitals — most of them seriously injured, with one in critical condition. No further information was immediately available.
Another tornado was reported in Dermott, Arkansas, injuring one resident but narrowly missing a nursing home.
"We had multiple trees and power lines down ... we could barely get access to the road," Fire Department Assistant Chief Damond Coffey said.
Severe flooding led the National Weather Service to issue a rare emergency alert for "life threatening" floods in Jonesboro, Arkansas, where several major roads were closed.
The University of Arkansas at Little Rock canceled classes when Coleman Creek, which runs through campus, caused several flash floods.
The storm is expected to move across the Southeast during Thursday morning, carrying the threat of damaging winds, hail and tornadoes from southeast Texas to west Georgia, the NWS said.
Lee Smithson, director of the Mississippi Emergency Management Agency, said workers were preparing for as much as 5 inches of rain in parts of the state through Thursday.
He added: "If you live in a mobile home, make plans to stay some place else."