THE SWARM! Here's what millions of Mayflies look like on the Power of 5 Doppler Radar! #ohwx @wews pic.twitter.com/gQHS0Ye4k4 — Mark Johnson (@MarkJWeather) June 24, 2015

Invasion of the mayflies pic.twitter.com/ER2yW7fTEC — Benjamin (@frankartb) June 24, 2015

.@MarkJWeather mayflies at put in bay Sunday night pic.twitter.com/pYGLZX5dKH — Flew (@Flewdog50) June 24, 2015

It's that time of year again: there's a swarm of mayflies hovering above Lake Erie big enough to be picked up by a local Doppler radar, and they're about to descend on Cleveland like an Old Testament plague.Expect to see them in the millions any day now. They don't bite or sting, but they will cover the entire surface area of any stationary object.Adult mayflies only live for about a day, and their only purpose besides being a general nuisance is to reproduce. The eggs and larvae can live at the bottom of the lake for around two years until they mature.There's no foolproof repellent that will get rid of them, but MayflyNews suggests using a broom or leaf blower. Using a hose will just leave an awful, fishy mess.Photos of the swarm are already starting to surface from out west, so here's a look at what we can expect, thanks to Twitter.