The annual "mayfly hatch," as it's so charmingly known in towns along the Mississippi River, has yielded a specific kind of repulsion the past few days as the pests that commonly hatch along river towns have burst onto everything from gas pumps to soda machines to busy roads, causing car accidents.

According to USA Today, the hatch this year started late Sunday night and has since taken over every identifiable space in some towns along the Mississippi River. The mayflies have even caused a bow echo on radar, as if there were a large rainstorm coming, according to the La Crosse, Wisconsin office of the National Weather Service.

From USA Today:

Up and down the Mississippi, the mayfly hatch has been a problem. About 80 miles upriver from here, police in Trenton, Wis., say mayflies may have triggered a three-vehicle crash Sunday.

The road about 50 miles southeast of Minneapolis had become slick from the mayflies Sunday evening, causing at least one of the drivers involved in the crash to lose control of her vehicle. Visibility was limited at the time of the crash because to the massive cloud of mayflies in the air, police said.

The mayflies die almost as quickly as they arrive: In under a few hours to a full day, the flies live their merry life terrorizing local river towns and then they meet their demise, just as the natural order demands.

But what about all those mayfly carcasses? Oh, don't you worry about that.

Last year, the Minnesota Department of Transportation had to call out snowplows to remove the dead mayflies from the highways.

[Images via KARE 11]