OMAHA, Neb. (AP) – Swarms of mayflies have emerged from under water along the Missouri River and are caking drivers’ windshields.

Mayflies spend 99% of their lives in water, but they rise above when they become winged adults to take part in a mating swarm. They quickly die after that.

But their mating season is a nuisance.

Pam Frana, a membership specialist for the Nebraska City Tourism and Commerce Department, blames the flooding for stirring up the mayflies.

Dominator Fuel in Rock Port, Missouri, sold out of windshield wiper fluid in light of the mayflies’ arrival.

Andrew Wagner, who works in Hamburg, Iowa, says covered windshields so much that drivers couldn’t see where they were going. But he says the situation is better now that flooding has gone down.