Swarm of mayflies cover police car, bridge in viral photos

'Tis the season for mayfly onslaughts, and, on Sunday night, the situation in Havana, Illinois became so serious it endangered area motorists, reports WCMH.

A bridge that stretches over the Illinois River was completely overrun with the insects, resulting in accidents and immobilized cars.

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On Monday morning, the Havana Police Department issued a warning on Facebook, writing, "Last night there was an invasion of Mayflies that has caused the bridge to be very dangerous. At one point they had piled 6 inches high and when ran over, became very slick."

The post also noted that workers from both the transportation and street departments were working to clear the area.

Get up close and personal with the Mayfly: