The mayflies have returned to Lake Erie communities ... “Sunday night, that was probably the worst swarm we’ve seen in quite some time," Port Clinton Mayor Mike Snider told the station.

The mayflies were concentrated near La Crosse, Wisconsin, often a focal point for annual swarms Their crushed bodies make roadways greasy - this year's Mississippi caused at least one car accident ...

Interestingly, mayflies can pose a problem for people who live near water. Because nymphs often reach maturity around the same time in the summer, they can create massive swarms and thick clouds ...

It was the second night in a row the bridge was closed. The cause, both times, was swarms of mayflies. WATCH: 'Blizzard' of mayflies swarm Route 462 bridge On Saturday night, they caused three ...