As severe thunderstorms threatened to hit parts of the Midwest and South on Wednesday, forecasters warned of potentially deadly flash flooding, strong tornadoes and baseball-sized hail.

At least one tornado was observed Tuesday night around Salina, Kansas, about 90 miles (145 kilometers) north of Wichita, according to the National Weather Service.

The potent storm system was expected to bring the threat of “significant, life-threatening flash flooding” starting Wednesday, according to the Weather Prediction Center, a part of the weather service.

The new flood threat came as residents in parts of Michigan continued to dig out from a weekend ice storm.

Floods could inundate towns, sweep cars away

Thunderstorms with multiple rounds of heavy rain were forecast in parts of Texas, the lower Mississippi Valley and the Ohio Valley beginning midweek and lasting through Saturday. Forecasters warned the storms could track over the same areas repeatedly and produce heavy rains and dangerous flash floods capable of sweeping cars away.

Parts of Arkansas, west Tennessee, western Kentucky and southern Indiana were at an especially high risk for flooding, the weather service said.

Rain totaling up to 15 inches (38 centimeters) was forecast over the next seven days in northeastern Arkansas, the southeast corner of Missouri, western Kentucky and southern parts of Illinois and Indiana, the weather service warned.

Tornadoes observed and more could be coming

At least one tornado was observed Tuesday night in Kansas, according to the weather service.

“Take cover now!” the weather service’s office in Wichita warned residents on the social platform X.

Overnight, storms could spin up tornadoes in Oklahoma as well as more in Kansas, forecasters said.

There could also be very large hail as well as severe wind gusts. The area at greatest risk for a strong tornado included Oklahoma City; Tulsa, Oklahoma; and Wichita, Kansas. The risk of large hail extended from Fort Worth, Texas, to Kansas City.

43 million people at risk for severe weather

A large swath of the nation from northeast Texas to Michigan was forecast to see the potential for high winds and tornadoes on Wednesday. The area at highest risk for severe weather is home 43 million people and many cities among the nation’s largest, including Chicago, Indianapolis, St. Louis and Memphis, Tennessee.

Dallas, Detroit, Milwaukee, and Nashville, Tennessee, were also at risk for severe storms on Wednesday.

Rainfall could be a once-in-a-quarter-century event

“We’re potentially looking at about two months of rain in just a handful of days,” Thomas Jones, a weather service meteorologist in Little Rock, Arkansas, said Monday.

The rainfall that eastern and northeastern Arkansas could see is something only expected once every 25 to 50 years.

The copious amount of rain in the forecast was rare, Jones said, and moisture from the Gulf was boosting the amount of precipitation the thunderstorms could release.

Wintry mix blasts Upper Midwest

In Michigan, crews tried to restore power Tuesday after a weekend ice storm toppled trees and power poles. More than 144,000 customers were without power in Michigan on Tuesday night, plus nearly 15,000 in Wisconsin, according to PowerOutage.us, which tracks outages nationwide.

In the mitten-shaped Lower Peninsula of Michigan, schools in several counties closed for a second day Tuesday. Sheriff’s deputies used chain saws to clear roads. Drivers waited at gas stations in lines that stretched for blocks.

More wintry precipitation was on the way: A mix of sleet and freezing rain could keep roads treacherous into Wednesday across parts of Michigan and Wisconsin, the weather service said.

Heavy, wet snow was forecast into Wednesday across the eastern Dakotas and parts of Minnesota.

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The story has been updated to correct that Tulsa is in Oklahoma, not Kansas.

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Associated Press Writers Isabella O’Malley in Philadelphia; Ed White in Detroit; Steve Karnowski in Minneapolis; and Hallie Golden in Seattle contributed.