Renewable Farming

Iowa ag officials trying to measure derecho wind damage to about 15% of Iowa corn

Yesterday morning, east central Iowa farmers were looking at a healthy, promising corn crop. By mid-afternoon, they saw thousands of acres flattened by “derecho” straight-line winds up to 110 miles per hour. 

Corn flattened in Greene County, Iowa, west of Des Moines

August 11, 2020 — Insurance companies, co-ops and Iowa ag officials are scrambling to evaluate the crop damage. You can get an idea of the geographic coverage from this 12-minute YouTube report by severe storm watcher Reed Turner.

In dozens of counties from Des Moines to Cedar Rapids, wind bursts caved in hundreds of empty steel grain bins on farms and at grain co-ops. Many grain facilities will be hard-pressed to clean up the collapsed bins and install new storage by harvest time. 

Update Aug. 12: We asked Iowa crop consultant Bob Streit for an estimate of affected corn acres. Various sources anticipate “up to 10 million acres impacted,”  he said.

Bob recalled previous seasons when several local blowdowns hit during ear fill. Recovering part of the downed ears depended a lot on weather through the remaining weeks of the season. 

Some growers were able to slow harvest to 1 mph and get under the stalks. “Drago corn heads are designed to slip under low-lying corn and pick it up,” Bob said.  

He added that the damage varied from field to field within the same locality, depending on a grower’s management. “Heavy anhydrous use showed more damage than metering out 28%, he said, because root penetration was deeper using the liquid N.  

So far, corn markets haven’t reacted significantly to the potential yield loss.

Update August 12: Bob Streit forwarded the photos below which he’d received in a message from Richard Feltes.  The message said:

These are aerial photos taken by a Pioneer agronomist. A little hard to see, but if you look closely you can see bins and buildings destroyed.  I drove a 60-mile loop in and out of the zone to the north.  Cars were lined up at any gas station you could find that had power. 

What was interesting was the northern edge where no buildings were destroyed but the corn was blown down like we have seen many times in the past. It will stand back up and have some minimal yield loss. 

But the main area of destruction is unbelievable. Farm after farm, mile after mile. Empty grain bins collapsed. Machine sheds torn apart. Houses did well. Roof and window damage but the structures are ok.  The corn is not. 

Where buildings and bins failed, the corn is like nothing I have ever seen — and have heard that statement from many farmers older than me. This corn was fighting drought and trying to fill kernels.  Now it is flat. Yield loss is significant. I have no idea how many millions of bushels of storage was destroyed, but very little will get replaced for this harvest. 

This is a rare event that will effect state yield.  It might take until we get RMA yields driven by crop insurance production reporting to get the real picture.  This will be a tough one for NASS and private crop tours.  This is going to be a long difficult harvest.


 The note from Feltes added: “I was up in a plane this afternoon… here’s some of the damage that goes for mile after mile after mile….  When we were in the air between McCallsburg and Garden City, all you could see was flat corn for miles in all directions.”

Update August 13:  A claims manager for a major casualty insurance company told us this morning that “We’re scrambling to respond to claims from across the Midwest. So far we’ve processed 600 claims — most from farmers with destroyed buildings and bins — and the phone keeps ringing.” 

Meanwhile The Washington Post newspaper asserted that 43% of Iowa’s crops were destroyed — a gross exaggeration. You can see by the few photos below that damage varies widely from field to field, with much of the variation depending on management practices. Farmers whose fertility and soils promoted deep rooting and healthy stalks withstood the 80 to 100-mph winds better than pancake roots and brittle stalks.


Update August 14: Ag Web published a storm update this afternoon at this link.  As with every disaster, neighbors pitch in to help. A friend of ours near Cedar Rapids, IA lost his machine shed, and family members from Elgin, IA spent two days salvaging what they could. While they worked, a couple from Oelwein drove up and offered the crew cold water from a big cooler, plus 5 gallons of gas for the crew’s chain saws.

Another friend of ours phoned from Indiana, asking “I feel compelled to round up some Hoosier buddies and come pick up pieces in Iowa… where would be first priority?”  

Update August 18:  Two market analysts report on AgWeb that derecho damage will trim corn production by 25 million to 75 million bushels this fall. That prospect hasn’t jolted markets substantially.  

Update September 4: Here’s a wrap-up report from Dale Fitzgibbons of Cedar Rapids, writing in the American Thinker.

Looking back at Hubbard from the southeast.  It’s easy to pick out the varying degrees of flattened corn. 

Hubbard was on the edge of the wind event so there is less damage toward town.





Brian and Brent Perry’s family farm.  Several bins destroyed with shed damage as well. 

Note how flat all the corn is in nearby fields.



Farm building site…several bins are destroyed.  All the corn within view is flat.

Bin site near Luther, north of Ames, IA