NORTH LITTLE ROCK, Ark. — A deadly storm system swept through the country’s midsection Friday, spawning ferocious tornadoes in Arkansas and Indiana, collapsing a roof at a packed concert venue in Illinois and leaving millions of people under tornado watches from Texas to Michigan.
In Arkansas, the governor declared a state of emergency Friday afternoon after officials said one person was killed in North Little Rock and two died in Wynne, about 100 miles to the east, in separate tornadoes. A state of emergency was also declared in Missouri in response to severe weather.
The mayor of Little Rock, Frank Scott Jr., said at least 30 people were hospitalized there and more than 2,000 homes were damaged. The storm did extensive damage to businesses and apartment complexes, the local police said.
In Wynne, Mayor Jennifer Hobbs told CNN that the town had been “cut in half by damage from east to west.” The precise scope of the damage was not immediately clear, and a dispatcher at the police department declined to comment early Saturday. A junior high school in the town had been opened for people seeking shelter and food.
One of the bands on the bill, Morbid Angel, said in a Facebook post that the band’s members were still sheltering in place at the venue. The National Weather Service reported “possible tornado damage” in Belvidere.
About 200 miles south, in the village of Sherman, Ill., more than a dozen homes were significantly damaged, Trevor J. Clatfelter, the mayor, said by phone Friday night. The storm, he said, had also caused major gas leaks, electricity outages and downed power poles across the village.
Roughly 150 miles to the east of Sherman, in Sullivan Country, Ind., two people were also killed after a tornado touched down, according to Sgt. Matt Ames with the Indiana State Police.
“We have a very dangerous situation right now,” he had said in an earlier interview with local news, adding that the local Veterans of Foreign Wars building was “completely gone.”
Pictures posted on social media by the V.F.W. chapter showed a mangled structure stripped of its roof. “Please pray for our community, and be patient as we overcome this tragedy,” the post said.
In Covington, Tenn., six patients were hospitalized after a tornado touched down in the city, Kimberly Alexander, a spokeswoman for the Baptist Memorial Hospital, said by phone on Friday night. On Facebook, the Covington Police Department described the city as “impassable.”
In addition to Arkansas, Illinois, Indiana and Tennessee, tornadoes were also reported to the National Weather Service across Wisconsin, Iowa and Mississippi.
The governor of Arkansas, Sarah Huckabee Sanders, said that officials there were on alert for the death toll to rise. “We’re hopeful that it doesn’t, but I think given the nature and the volatility of the situation, we’re certainly preparing that it could,” she said at the news conference on Friday night.
Mr. Scott, Little Rock mayor, said at a news conference on Friday night that more than 30 people had been hospitalized in the city. Many residents had also been displaced, he added.
In an interview, Mr. Scott said at least 2,100 homes had been destroyed by the tornado and that it was too soon to know how much the damage might cost.
“I suspect we’ll be working through the damage for a week, if not longer,” Mr. Scott said.
In addition to the tornado emergency for parts of Little Rock, forecasters also declared an emergency for parts of nearby Sherwood and Jacksonville, Ark. As dawn broke on Saturday, more than 400,000 customers across 10 states were still without power, according to PowerOutage.us, which aggregates data from utilities across the country.
Baptist Health’s medical centers in Little Rock and North Little Rock were already treating a total of 21 patients — five of whom were in critical condition — Cara Wade, a spokeswoman, said early Friday night. The two hospitals were anticipating a surge of additional patients.
Joshua Cook, a spokesman for CHI St. Vincent Infirmary, said the hospital’s emergency department was seeing a “high volume of people with injuries,” but he did not know their severity.
Leslie Taylor, a spokeswoman for the University of Arkansas for Medical Sciences, said that at least three trauma patients had been taken to the hospital.
In Indian Hills, a middle-class neighborhood in North Little Rock, about a dozen homes appeared to have been damaged, including the home of Mildred Loy, 95, who said she had nearly been crushed when a tree fell through her roof.
Ms. Loy said that her caregiver had scooped her off the sofa and moved her to the hallway, where she climbed on top of Ms. Loy to protect her. “As she laid down, we heard boom,” Ms. Loy said. “It crashed right where I was sitting.”
Meteorologists at the National Weather Service office in Little Rock had to move to a tornado shelter on Friday afternoon, as it became clear that their office was in the tornado’s path. The Memphis office of the Weather Service planned to issue warnings and monitor the weather on their behalf, said Desiree Meadows, a meteorologist in Memphis.
Stephanie Carruthers, a manager at Trio’s restaurant in Pavilion in the Park shopping center in Little Rock, said about 25 employees and customers safely rode out the storm in the kitchen.
“It blew over so fast,” Ms. Carruthers said. “It started raining real hard, so we all ran into the kitchen. I turned around, and the front doors just blew up.”
Officials from fire departments in the Little Rock area said that search and rescue teams were on the ground, checking homes door to door for injured residents.
“At this time it doesn’t seem to be very many,” said Captain Dustin Free, a spokesman for the North Little Rock Fire Department. But, he added, the situation was still very fluid.
Footage posted to social media appeared to show a large tornado touching down in Sigourney, a town of about 2,000 people about 70 miles southwest of Cedar Rapids, Iowa. Other images from the region appeared to show torn-apart buildings and upturned cars.
Manny Galvez, a resident of Coralville, a city about 20 miles south of Cedar Rapids, said he had hunkered down in his basement just before 5 p.m. “That was terrifying,” Mr. Galvez said in a phone interview, adding that he had emerged about 40 minutes later to find nearby homes torn apart and trucks upturned.
The storms could affect parts of Mississippi that were devastated last week by tornadoes that left at least 26 people dead.
President Biden on Friday visited Rolling Fork, the Mississippi community hit hardest by the tornadoes last week. Tornadoes killed 13 people and destroyed homes and businesses in Rolling Fork and in surrounding Sharkey County.
Reporting was contributed by Robert Chiarito, Amanda Holpuch, Derrick Bryson Taylor, John Keefe, Euan Ward and Tim Wallace.