Nightmarish 'Mayfly Blizzard' Closes Bridge For 2 Nights, Causes CrashesAuthorities say a Pennsylvania bridge has been closed for a second straight night because of swarms of mayflies so thick that they caused accidents.
Swarming Mayflies Prompt Bridge Closure, Motorcycle CrashesAuthorities say a swarm of mayflies was so dense that it caused a series of motorcycle crashes and prompted them to close a Pennsylvania bridge.
Mayflies Invade Pittsburgh's North ShoreMayflies are back again – this time at PNC Park on Pittsburgh’s North Shore.