LAKE CITY, Ark. (AP) — Tornadoes and violent winds flattened homes and ripped apart buildings from Oklahoma to Indiana in the first round of storms that are expected to bring record-setting rains and life-threatening flash floods across the nation’s midsection in the coming days.

At least six people were killed in western Tennessee, Missouri and Indiana in the first wave on Wednesday and early Thursday that spawned powerful tornadoes — one launching light debris nearly 5 miles (8 kilometers) above the ground in Arkansas.

Tennessee Gov. Bill Lee, after touring the devastation, said Thursday it was too early to know whether there were more deaths as searches persisted.

Workers on bulldozers cleared rubble along the highway that crosses through Lake City, Arkansas, where a tornado packing winds of 150 mph (241 kmh) sheared the roofs off homes, collapsed brick walls and tossed cars into trees.

“I don’t really know how to explain it,” said Cody Ferguson, who hid in a storm shelter with neighbors while the twister roared above them. “Just real loud rumbling, a lot of bangs, debris.”

His home that he built from the ground up was demolished, and he said a neighbor across the street was seriously injured.

Those killed included a man and his teenage daughter whose home was destroyed in western Tennessee, and a man who died after his pickup struck downed power lines in Indiana.

Forecasters on Thursday warned of catastrophic weather soon ahead. Satellite imagery showed thunderstorms lining up like freight trains — taking the same tracks over communities in Arkansas, Tennessee and Kentucky, according to the national Weather Prediction Center in Maryland.

The bull's-eye centered on a swath along the Mississippi River and included the more than 1.3 million people around Memphis, Tennessee.

More than 90 million people were at risk of severe weather — from Texas to Minnesota and Maine, according to the Oklahoma-based Storm Prediction Center.

Flash flood threat looms over many states

Round after round of heavy rains are expected in the central U.S. through Saturday and could produce dangerous flash floods capable of sweeping away cars. The potent storm system will bring “significant, life-threatening flash flooding” each day, the National Weather Service said.

With more than a foot (30 centimeters) of rain possible over the next four days, the prolonged deluge “happens once in a generation to once in a lifetime,” the weather service said. “Historic rainfall totals and impacts are possible.”

Water rescue teams and sandbagging operations were being staged across the region, and the Federal Emergency Management Agency was ready to distribute food, water, cots and generators.

Water rescues were already underway on Thursday in flooded parts of Nashville, Tennessee, where the rain could persist for days after an unnerving night of tornado warnings that drained the batteries of some sirens across the city, the fire department said.

Western Kentucky residents were bracing for historic amounts of rain and flooding in places that normally don’t get overwhelmed by water, Gov. Andy Beshear said.

Flash flooding is particularly worrisome in rural areas of the state, where floodwaters can quickly rush off the mountains into the hollows. Less than four years ago, dozens died in flooding across eastern Kentucky.

Extreme flooding across the corridor that includes Louisville, Kentucky, and Memphis, which have major cargo hubs, also could lead to major shipping and supply chain delays, said Jonathan Porter, chief meteorologist at AccuWeather.

Forecasters attributed the violent weather to warm temperatures, an unstable atmosphere, strong wind shear and abundant moisture streaming from the Gulf.

Tornadoes leave path of damage, and more could be coming

Under darkened skies Thursday morning, the remains of a used car dealership in Selmer, Tennessee, stood roofless and gutted by the storm. Shards of debris scattered across the car lot and wrapped around mangled trees. Some homes were leveled to their foundations around the town where three tornadoes were suspected of touching down.

“Thank God we came out without a scratch,” said Willie Barnes, who had only enough time to get in a bathroom with his wife before the storm wrecked his home.

The Tennessee Highway Patrol released video of lightning illuminating the sky as first responders scoured the rubble of a decimated home in Selmer early Thursday morning, looking for anyone trapped.

In neighboring Arkansas, a tornado near Blytheville lofted debris at least 25,000 feet (7.6 kilometers), according to weather service meteorologist Chelly Amin. The state's emergency management office reported damage in 22 counties from tornadoes, wind gusts, hail and flash flooding.

Mississippi's governor said at least 60 homes were damaged. In far western Kentucky, four people were injured while taking shelter in a vehicle under a church carport, said the emergency management office in Ballard County.

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Walker IV reported from Selmer, Tennessee, and Seewer reported from Toledo, Ohio. Associated Press writers Andrew DeMillo in Little Rock, Arkansas; Jonathan Mattise in Nashville, Tennessee, Seth Borenstein in Washington; Isabella O'Malley in Philadelphia; Kathy McCormack in Concord, New Hampshire; Bruce Schreiner in Louisville, Kentucky; Jeff Martin in Atlanta; Hallie Golden in Seattle; and Ed White in Detroit contributed to this report.