Monday’s derecho across the Corn Belt and Midwest laid siege to more than 10 million acres of Iowa’s corn and soybean crop, devastating farmers and capping off what has already been a difficult few years of farming for many.

Up to 43% of the state’s corn and soybean crop have suffered damage from the storms that brought winds exceeding 100 miles per hour at times, a severe blow to a 10 billion-dollar industry that’s central to the Hawkeye State’s economy. The magnitude of the battered vegetation was even visible on the same weather satellites used to track Monday’s violent thunderstorms.

State officials continued to survey the damage Wednesday in hopes that some of the crop may be salvageable. Iowa Republican Gov. Kim Reynolds issued a disaster proclamation for 20 Iowa counties, freeing up state funding for disaster response and recovery. The state is also making grants available to low-income families who find themselves faced with food, repair, or temporary housing expenses in the wake of the disaster.

“Though it will take days or weeks to know [the] full scope of damage, initial reports are significant,” said Reynolds at a news conference on Tuesday. She noted that the state is working to frame its storm response while also managing the ongoing covid-19 epidemic.

Drive-up covid-19 testing sites in Cedar Rapids, Davenport and Marshalltown were closed Monday and Tuesday. “They are working to reopen those as quickly as possible,” said Reynolds.

Satellite imagery on Tuesday captured the scope of the agricultural destruction. At least two significant swaths of wind damage can be seen, particularly north of Interstate 90. Radar signatures indicate the core of 90 to 100 mph winds may have been between 30 and 50 miles wide at times.

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Winds were clocked at 112 mph in Midway, Iowa, about 10 miles north of Cedar Rapids. A gust to 100 mph was recorded nearby in Hiawatha.

A personal weather station measured a gust of 106 mph in Marshalltown, a city of 27,000 northeast of Des Moines. The airport gusted to 99 mph as the storms barreled through.

All told, more than 700 instances of damage or severe weather were reported to the National Weather Service following the passage of the derecho, which wrought havoc along a track some 700 miles long from Nebraska to Indiana.

Jan Dutton, chief executive of Prescient Weather, a private forecasting group specializing in predictions for agricultural interests, said between 180 and 270 million bushels of corn were likely affected. His technique employed his company’s corn production forecast, which predicts crop yields based on antecedent and ongoing weather conditions.

“I saw the satellite image, outlined the counties in Iowa that were affected by the derecho, and looked at what counties were inside the domain,” explained Dutton.

He said that figure causes a serious dent in yield for Iowa, but that other states could help soften the deficit.

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“Total corn production for the U.S. is going to be 16 billion bushels,” said Dutton. “The amount impacted is like one purchase from China.”

Iowa is the number one producer of corn in the United States, comprising roughly a sixth of nationwide yields in 2019, when 2.58 billion bushels were harvested. The U.S. Department of Agriculture reports that an estimated 15.3 billion bushels of corn will be produced nationwide in 2020. Iowa has been the country’s top corn producer every year for the past 26 years.

Not all of the corn affected by the derecho was necessarily destroyed, however. It will take time for agronomists to assess the health of corn plants affected, said Keely Coppess, communications director for the Iowa Department of Agriculture.

“A lot of the corn is in the later development stages,” said Coppess. “Some is at a 45-degree angle, but it may attempt to stand back up. But it’s really too soon to tell. We’ll know more in a week or so.”

Carl Jardon, the vice president of the Iowa Corn Growers Association, said in a statement that the derecho affected the entire width of the state.

“Harvest will begin shortly and one-third of Iowa’s crop are flattened, it’s hard to tell at this point whether all the corn will recover and the impact of potential yield,” he said. “2020 has been a year of downfalls for the farmer. It has been one hit after another with trade disputes, low demand and attacks on ethanol and the Renewable Fuel Standard, on top of a global pandemic and the lowest corn prices in over a decade.”

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Corn is typically harvested in Iowa between late September and mid October.

Corn plays a significant role in Iowa’s climate. By releasing water into the atmosphere in a process called evapotranspiration, it has been shown to increase the dew point and subsequently the humidity. That can lead to higher heat indexes during heat waves, and can also contribute to fueling severe thunderstorms.

The vicious windstorm came by surprise on a morning when most of Iowa was only predicted to see very isolated severe weather. The National Weather Service Storm Prediction Center (SPC) had issued a level 1 out of 5 “marginal risk” of severe weather for most of Iowa just a few hours before winds began gusting upward of 90 mph in the central part of the state. Only after the storms began their violent march to the east did SPC issue a dramatic upgrade in their storm outlook to a level 4 out of 5 “moderate risk” from central Iowa east to Chicago. In areas to the east of the Iowa cornfields, the forecast is considered a success.

Derechos are notoriously difficult to predict, since the atmospheric ingredients for them are in place during much of the summer; yet those ingredients are rarely combined in the necessary way to generate such a fierce storm system.

“It was very bizarre . . . it’s been a whirlwind,” said Brandi Snyder, a spokesperson for the Iowa Corn Growers Association. “I remember my husband telling me it will be cooler, like 75 [degrees] . . . he said, ‘there won’t be much heat.'”

But when she awoke Monday morning, it was hot and humid – even by Iowa standards.

“I woke up and noticed all of our windows were fogged over,” she said. “You could just feel the extreme humidity. It was weird out.”