The powerful derecho windstorm that tore through central and eastern Iowa on Aug. 10 left a wide path of destruction to crops, buildings, grain bins, power lines, trees and more. Winds reached over 100 mph in the hardest-hit areas.
Standing in a field of flattened and broken cornstalks on Aug. 21, Dwayne Gerlach was unsure how much of his family’s 2020 corn crop would be lost. Stalks that were snapped off were dead, and some plants were completely flattened. But many of the plants that were blown over and leaning down close to the ground were still green, and ears and kernels were continuing to mature.
Dwayne’s grandnephew, Seth Gerlach, was with Dwayne inspecting their fields near Nevada in Story County. “As a young farmer, this is my first derecho and, hopefully, my last,” said Seth, age 26. Dwayne, who’s been farming since 1960, has seen and experienced other windstorms over the years “but never with as much widespread severe damage as this one,” he said.
Harvesting downed corn
Some farmers estimate they have fields with as little as 10% damage, and some fields with 80% or more. “With downed corn, the question is we don’t know if we can get it all picked up with the corn head and into the combine,” Dwayne said. “It will be a slow and difficult harvest. Much will depend on the weather.”
Some farmers will chop their downed corn for silage to feed to cattle. The Gerlachs will harvest their corn for grain, as they don’t have cattle. To help recover downed corn, they’ll mount a pickup reel on the corn heads of two combines.
Farmers are more hopeful for soybeans, as the plants were twisted and leaning, but most fields stood back up the next day or so after the storm. Soybeans were still growing when the derecho hit, whereas cornfields were beyond growth stage and were in the grain maturity phase. Some corn and soybean fields were hit by hail, although most of the derecho damage was due to hurricane-like wind.
“The severity of damage varies field by field, but some acres are a total loss, and it will not be feasible for farmers to harvest them,” said Iowa Secretary of Agriculture Mike Naig. “We are continuing to work with farmers, USDA and crop insurance providers to identify solutions as we approach a very challenging harvest season.”
Millions of acres impacted
USDA’s Risk Management Agency reports 57 counties in Iowa were in the path of the storm. About 8.2 million acres of corn and 5.6 million acres of soybeans are in that area that may have been impacted by high winds. Using satellite imagery USDA and the Iowa Department of Agriculture estimate 36 counties were hit hardest, and 3.5 million acres of corn and 2.5 million acres of soybeans are grown in that region.
The massive derecho destroyed grain bins and storage facilities for tens of millions of bushels of corn, both on farms and at commercial grain elevators. Preliminary estimates are that more than 57 million bushels of commercial grain storage structures were seriously damaged or destroyed. Co-ops in Iowa estimate it will cost more than $300 million to remove, replace or repair damaged bins.
In addition to reduced storage capacity and lower yields, other problems loom. Corn lying down on the ground is more susceptible to toxins forming in the grain, raising quality concerns. Also, storm debris blown into fields and hidden by crops can damage the combines and other equipment, requiring costly repairs.