Emergency crews were on scene over the weekend to clear a bridge after bugs took over.
On Saturday night, Teena Franzen recorded the incident while riding with her son in a Sabula police car.
Watch the full video at the bottom of this post.
"I've lived in Sabula since '75, I've never seen that many before, ever," said Teena Franzen of Sabula.
A pair of motorcycles had lost traction trying to move through the piles of mayflies. Thankfully no one was hurt.
"Biggest thing I noticed was after cars were stopped and sitting for so long while we're trying to get cars moving again is they were probably piled knee high in front of their headlights from just sitting there," said Reserve Officer Stephen Thayer of the Sabula Police Department.
"We had Iowa DOT came in with a snow plow and actually plow them off and then sand it because it was still pretty slippery. And then Illinois plowed their side," Thayer added.
The Iowa Department of Transportation will keep lights on the bridge turned off over the next few weeks in order to keep the bugs off the bridge.