LAKE CITY, Ark. >> Standing alongside the twisted steel tractors on his family farm in northeast Arkansas on Thursday, Danny Qualls looked on while friends and relatives helped him begin cleaning up.

The home where he spent his childhood but no longer lives was flattened by one of many tornadoes that left behind destruction from Oklahoma to Indiana — the first in a round of storms expected to bring historic rains and life-threatening flash floods across the nation’s midsection in the coming days.

“My husband has been extremely tearful and emotional, but he also knows that we have to do the work,” Rhonda Qualls said. “He was in shock last night, cried himself to sleep.”

At least six people were killed in western Tennessee, Missouri and Indiana in the initial wave on Wednesday and early Thursday that spawned powerful tornadoes — one of which launched light debris nearly 5 miles into the air above Arkansas.

Tennessee Gov. Bill Lee said it was too early to know whether there were more deaths as searches persisted.

“The devastation is enormous. What’s most difficult about it is, you know that those are lives destroyed,” Lee said in the hard-hit town of Selmer. “In some cases, true life lost, but in other cases, everything people owned, up in trees.”

Those who died included a Tennessee man and his teen daughter whose home was destroyed, and a man whose pickup struck downed power lines in Indiana. In Missouri, 68-year-old Garry Moore, who was chief of the Whitewater Fire Protection District, died while likely trying to help a stranded motorist, according to Highway Patrol spokesperson Sgt. Clark Parrott.

Forecasters warned Thursday 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.

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

Round after round of heavy rains were 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 of rain possible over the next four days, the prolonged deluge is something that “happens once in a generation to once in a lifetime,” the weather service said. “Historic rainfall totals and impacts are possible.”

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