Millions of mayflies swarmed in Pennsylvania on Saturday night, creating blizzard-like conditions on a bridge, local firefighters said.
During the swarm, the Veterans Memorial Bridge between Wrightsville and Columbia became covered in a 1-inch layer of dead insects, Lancaster Online reported. Officials closed the bridge as the road became slick and visibility was limited.
The conditions the swarm caused on the roadways resulted in several crashes, according to the Wrightsville Fire Department.
"The sights and smell are lingering within the station one day later," the department Facebook page said. "Firemen removed piles at least one foot in height from apparatus last night and still got a trash can full from the upper area Rescue 1's pump today."
According to the York Daily Record, it was the second time mayflies have swarmed the bridge since new LED cast-iron lights were installed in 2013.
Mayflies hatch in rivers and lakes, developing wings only in their adult stage. They live as adults less than 24 hours, and large populations often mature at the same time.