A massive swarm of mayflies, detected by National Weather Service weather radar starting after 9 p.m. Thursday, invaded downtown Burlington, Iowa along the Mississippi River. Piles of flies were inches deep in spots. The insect swarms are coming up the Mississippi, towards the Twin Cities. Right now, areas south of the Twin Cities metro are … Continue reading Mayfly Madness: This Massive Swarm of Mayflies Was so BIG it Was Detected on NWS Weather Radar While Invading Towns Along The Mississippi River and Heading Towards the Twin Cities