Powerful rains flooded Chicago streets Sunday, trapping vehicles and forcing NASCAR officials to call the Xfinity Series Race scheduled to run through the city’s downtown.

The National Weather Service reported that some areas had received over seven inches of rain and several roadways remained flooded. The Illinois State Police said portions of Interstate 55 and Interstate 290 have been closed because of flooding, with at least 10 cars trapped in water on Interstate 55, WLS-TV reported.

Trains had also stopped in some parts of the city.

NASCAR officials had planned to complete the last half of an Xfinity Series race Sunday morning after it was canceled Saturday due to lightning. But heavy rain Sunday caused officials to cancel the race and declare Cole Custer the winner.

Meanwhile, more than 110 million Americans are under hazardous weather alerts as severe thunderstorms and dangerous Heat levels persist across the country, weather forecasters warned this weekend. Parts of the South, Midwest, and East Coast remained under severe thunderstorm alerts Sunday after several days of extreme weather conditions.

Since Thursday, nearly 700 incidents of damaging winds have been reported in the central, southern, and eastern United States, according to the National Oceanic and Atmospheric Administration.

“DO NOT drive or walk across flooded roads,” the weather service in Chicago tweeted. The weather service also warned that the flooding could be “life-threatening” due to multiple impassable roads, overflowing creeks and streams, and flooded basements.

Threats of thunderstorms, hail, tornadoes

The threat of dangerous and severe thunderstorms will extend across parts of the Midwest and South, from Tennessee to New Jersey, according to AccuWeather.

Large hail and damaging winds with a chance of a small number of tornadoes are forecast for the region, AccuWeather said. Some storms will also produce lightning strikes and wind gusts between 60 and 70 mph, said AccuWeather meteorologist Alex DaSilva.

With a large number of people expected to be outdoors for the Fourth of July weekend, AccuWeather meteorologists warned people to move and stay indoors at the first sign of a thunderstorm.

On Monday, thunderstorms are expected over areas of Vermont, New Hampshire, the Carolinas, and Mississippi, AccuWeather said.

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West, Southeast under intense heat

While temperatures across the South have begun to cool down, parts of the Southeast and West are under heat alerts. Excessive heat warnings were issued for the Desert Southwest region, including areas in Arizona and California.

The heat is expected to last through the week with portions of Oregon expecting hot temperatures for the Fourth of July, according to the weather service.

“Heat-related danger remains elevated due to the longevity of this heat wave,” the Storm Prediction Center said.

The weather service in Los Angeles said heat exhaustion and heat strokes are possible during hot and humid weather. Residents were advised to “be on guard” and avoid leaving children, pets, and elderly people in hot cars, the weather service in Los Angeles said.

High fire conditions are also expected. The Angeles National Forest warned that fireworks are a risk and prohibited on federal public lands.

US weather warnings, advisories map

Contributing: Jeanine Santucci, USA TODAY; Associated Press