Illinois bridge turned slick by 6-inch-deep mayfly infestation

HAVANA, Ill., June 27 (UPI) -- An Illinois police department issued a warning to residents after an overnight mayfly invasion caused an insect-covered bridge to turn slippery.

The Havana Police Department urged residents to "use caution" on the city's Scott W. Lucas bridge Monday after the mayfly infestation caused the structure to become covered in the insects.

"At one point they had piled 6 inches high and when ran over, became very slick," the department said in a Facebook post.

Police said the City of Havana Street Department and Illinois Department of Transportation were working to clear the streets.