A bit dated from a month ago, but I always find the stories of nature on crack fascinating. Just over a month ago, radar in Wisconsin picked up a disturbance. This turned out to be a ‘massive’ (billions of insects) Hex hatch (Hexagenia Bilineata), which rose on the Mississippi River and moved across Wisconsin, Iowa and Minnesota. Hex Mayfly are much revered by fly fishers because they are big insects and trout love them at last light. 

Miss Mayfly Hatch
Mississippi Hex Mayfly Hatch on Radar
hex_pine_river
Central Wisconsin Trout Unlimited (CWTU) Photo Source
super hex hatch
Mike Hamernik
Hexagenia bilineata
Hexagenia Bilineata