US / strange stuff Culprit Behind 3 Crashes and Bridge Closing? Mayfly Swarms That is not snow in the photos By Newser Editors and Wire Services Posted Jun 14, 2015 4:10 PM CDT Copied A swarm of mayflies hovers over the Route 462 bridge over the Susquehanna River late Saturday, June 13, 2015, between Columbia and Wrightsville, Pa. (Blaine Shahan/LNP via AP) Authorities say a swarm of mayflies was so dense that it caused a series of motorcycle crashes and prompted them to close a Pennsylvania bridge. The mayflies swarmed around the lights on the bridge and then fell to the ground, making piles several inches deep on the roadway, reports Lancaster Online. Police in West Hempfield Township in Lancaster County said the Route 462 bridge between Columbia and Wrightsville was shut down at about 10:30pm yesterday. Chad Livelsberger, chief of the Wrightsville Fire Company, said three motorcycle crashes occurred because of the flies. There was no immediate word on whether anyone was injured in the accidents. Officer Brad Rohrbaugh said the bridge was reopened sometime before 6am today. (More strange stuff stories.) Report an error