Tornadoes tore through Louisiana on Monday, killing at least one person and threatening huge swaths of Mississippi, western Alabama and the Florida Panhandle, authorities said.
About 11 million people were affected by the wild storms during the day and through the night, according to the Storm Prediction Center of the National Oceanic and Atmospheric Administration.
The rash of twisters comes from a monster 2,000-mile-long storm system that stretches from Colorado to New England.
Some points of the Rocky Mountains recorded 40 inches of snow on Monday, and transportation officials braced for a travel nightmare in the Northeast, where rain and snow were forecast to fall on airports and roads Monday night and Tuesday morning.
Temperatures in tornado-afflicted regions are 10 to 20 degrees above average for this time of year, meteorologists said. The heat, combined with the system's high winds, are fueling severe storms through the night, despite the loss of daytime sunshine that usually boosts tornadoes.
Images from the region showed what appeared to be twisters near Foxworth and Columbia, Mississippi. The National Weather Service issued tornado warnings across the state and confirmed one twister near the community of Mize, southeast of Jackson.
"Take cover now if you are in the path of this dangerous storm!" the agency tweeted.
In Vernon Parish, Louisiana, about 240 miles northwest of New Orleans and 120 miles south of Shreveport, at least one person was killed by the extreme weather, according to sheriff's deputies and the state's Office of Homeland Security and Emergency Preparedness.
"We've got damage at lots of places. We've got a church where the fellowship hall is torn all to pieces," Chief Deputy Calvin Turner said. "Some homes are hit. Right now, we're having trouble just getting to places because of trees that are down."
In Alexandria, in Rapides Parish about 115 miles southeast of Shreveport, video showed authorities marching hand in hand with students out of Hope Baptist Church. The storm appeared to have demolished the church's school building, but none of the dozens of children who are enrolled there were injured, Rapides Chief Deputy Mark Wood told NBC News.
Wood said the students had been moved into another building earlier.
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Emergency planners throughout the Deep South feared the threat of nocturnal tornadoes hitting overnight.
Nighttime twisters are more than twice as deadly as daytime tornadoes because it's so much harder to see them coming and potential victims are asleep — not watching TV, listening to the radio or surfing online to get evacuation warnings.
"Chance for strong storms starting this evening," according to a statement by NOLA Ready, the city of New Orleans' emergency preparedness operation. "Stay weather aware and have a way to receive emergency alerts."