Corn plants are pushed over in a damaged field in Tama, Iowa. Iowa Gov. Kim Reynolds said that early estimates indicate that 10 million acres, or nearly a third of the state’s cropland, was damaged in a powerful storm.

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Corn plants are pushed over in a damaged field in Tama, Iowa. Iowa Gov. Kim Reynolds said that early estimates indicate that 10 million acres, or nearly a third of the state’s cropland, was damaged in a powerful storm.

Daniel Acker/Getty Images

Hundreds of thousands of people remain without power in Iowa and Illinois, and some roads are still impassable, after a powerful windstorm wreaked havoc in the Midwest on Monday. The violent winds spread from South Dakota to Ohio, topping 100 mph in some places.

The storm system, called a derecho, flattened crops, toppled trees and crumpled grain silos. Days later, communities are still assessing the damage.

Some Iowa school districts are delaying their start dates because of the damage, Iowa Public Radio reports. The storm damaged school buildings and knocked out power; some school districts want to give staff and students’ families time to deal with their own damages, or their lack of power, Internet and cell service.

“I’ve never seen a storm like this,” Gary DeLacy, superintendent of Clinton schools, told Iowa Public Radio.

Iowa farmers took a double hit from the storm, The Associated Press reports. Bins filled with last year’s harvest were torn open, while fields planted with this year’s corn were flattened.

In this aerial image from a drone, damaged grain bins are shown at the Heartland Co-Op grain elevator in Luther, Iowa, on Tuesday.

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In this aerial image from a drone, damaged grain bins are shown at the Heartland Co-Op grain elevator in Luther, Iowa, on Tuesday.

Daniel Acker/Getty Images

Iowa’s corn crop alone is worth billions of dollars. Gov. Kim Reynolds says a full assessment of the damage to the corn and soybean crop will take days or weeks, but that initial estimates indicated 10 million farm acres were damaged.

In Northern Illinois, a vocational farm that distributes produce for free to food-insecure neighborhoods was hit hard by the storm, Northern Public Radio reports.

One greenhouse “has pretty much been demolished,” DeKalb County Community Gardens communications director Jackie DiNatale told the station. Repairing the damage — estimated at some $50,000 — is difficult, because power is still out at the farm.

Strong winds were also felt in Chicago, where roofs were toppled from buildings and debris blocked streets and sidewalks, as Araceli Gomez Aldana of member station WBEZ reported for NPR’s Newscast unit earlier this week.

As it barreled eastward across the country, the storm system traveled 770 miles in just 14 hours, according to the National Weather Center’s Storm Prediction Center.