just west of cedar rapids, farmers like lance lillibridge are still assessing just how much of their crop was destroyed. >> our corn is really twisted up pretty bad. it's still harvestable, unlike a lot of people who were zeroed out, their corn was totally wiped out. >> reporter: lillibridge is vice president of the iowa corn growers association. he says hundreds of farmers were affected this year, as the windstorm flattened their crops and burst open grain bins. and the cleanup is still going on. >> so, this one is by far probably the biggest weather event i've ever seen in my lifetime. >> reporter: the u.s.d.a. estimates at least 550,000 acres of iowa corn won't be harvested this fall because of the derecho, and lillibridge says crop insurance doesn't fully cover what was lost for farmers. >> financially, it's devastating. even though we have federal crop insurance, that'll never, ever cover what some people have lost. crop insurance will only cover, depending on how much of it you buy, maybe 70-90% of what you've lost. if you have two or three of these events in a row, you know, m