Tornadoes ripped across the Midwest and into the South on Wednesday, leveling homes and businesses, killing at least a dozen people and injuring more than 100 in Illinois, Missouri and Tennessee.
Forecasters warned that another major storm with tornado potential was due Friday in the Lower Mississippi River Valley.
The southern Illinois town of Harrisburg bore the brunt of the fatalities, with six, from a storm packing winds of up to 166 mph, officials said. Three other people died in Missouri in the early morning, and another three in Tennessee in the evening.
Harrisburg residents described scenes of terror.
"It just roared," said Pat Talley, 76, who huddled in a hallway closet during the storm and was one of the lucky ones — her home survived unscathed.
But elsewhere, "there's just so much damage," she said. "It's like a dream."
Diana Turner awakened to wailing storm sirens just before 5 a.m., put on her bathrobe and opened the back door of her mobile home to investigate.
Within moments, the tornado had touched down, collapsing the walls and trapping her under debris. Her husband, Charles, was trapped under a cabinet in the bathroom, but both suffered only minor injuries.
"There's people out there a lot worse off than we are," Diana Turner said. "We're very, very lucky."
The twister peeled off walls, shattered windows, hurled mattresses into trees and reduced many homes in the community of 9,000 to debris.
Harrisburg Mayor Eric Gregg said residents, no strangers to harsh weather, were shocked by the extent of the damage.
"We have devastation in our community like we have never seen," he said.
In Missouri, the country music resort of Branson took heavy damage, including to its downtown strip of music venues. But no one was known to have died there. Another month and the toll could have been far worse: That's when tourist season begins.
"These storms have caused extensive damage across Missouri, and widespread damage and debris continue to pose significant risk to lives and property," Missouri Gov. Jay Nixon said. He declared a state of emergency, as did Illinois Gov. Pat Quinn.
John Moore, owner of the damaged Cakes-n-Creams '50s Diner & Dessert Parlor, said the Branson tornado "appeared to jump side to side," moving through the convention center, across a lake and into a housing division.
One person died in Cassville, Mo., one in Stoddard County and one in Dallas County.
Late in the day, the storm system crossed into Tennessee, killing two people in Cumberland County and one in Dekalb County, according to Jeremy Heidt, spokesman for the state's Emergency Management Agency.
The Harrisburg twister, the deadliest in the U.S. so far this year, marked an early arrival to tornado season. It follows a year in which more people were killed by tornadoes than in the previous eight years combined, according to National Weather Service statistics.
The tornadoes were generated by a powerful storm that blew down from the Rockies and over to the Ohio and Tennessee river valleys. Twisters also damaged areas of Kentucky and Kansas.
Meanwhile, a separate storm was expected to descend on the Lower Mississippi River Valley on Friday, said Greg Carbin, a meteorologist with the National Weather Service's Storm Prediction Center in Norman, Okla. It could bring tornadoes to a region including Alabama, Mississippi and Tennessee.
Late Wednesday, Kim Dunn surveyed the aftermath of the storm while clearing debris at her Harrisburg house.
Dunn said she was pulling into the Harrisburg Medical Center, where she works, when she heard the sirens. After calling her husband, she left the damaged building, where a wall fell.
She could not drive down her street because of the debris, she said, so she parked her car and walked home by flashlight.
"The really weird part was hearing people yell for help everywhere," she said. "And you couldn't see anybody."
When she got home, ceiling tiles were missing, half of the carport was flattened and parts of the roof were gone. But her husband, son and mother were unharmed.
Hennessy-Fiske reported from Houston and Ruthhart from Chicago. Chicago Tribune reporters Alissa Groeninger and Ryan Haggerty and special correspondents Tara Kulash and Sarah Schneider contributed from Harrisburg.