Mayflies take over the Midwest
At about 8:45 p.m. on the night of July 20, over the Mississippi River, this happened:
The happening registered on the National Weather Services’ radar as “light-moderate” rain. But what you’re actually seeing is the periodic emergence — better described as massive swarm – of mayflies. The NWS is downright giddy about what must, for those nearby, have seemed like something out of a horror movie:
By late evening, mayflies were swarming in La Crosse, La Crescent, Stoddard and points up and down the river. While the emergence of mayflies from their river bottom mud dwelling can occur at various times through the warm season depending on the species, this particular emergence was that of the larger black/brown Bilineata species. The radar loop below shows the reflected radar energy (reflectivity) from 835 pm to just after midnight. The higher the values (greens to yellows) indicate greater concentrations of flies. Note how the swarm is carried northward over time.
Yes, do note that. Also note this “grotesque natural phenomenon” is being blamed for a three-car crash that left one person hospitalized, as well as for leaving behind a “big, slimy mess.” It’s kind of what the flies are going for, as Wired explains:
Mayflies emerge synchronously around dusk to avoid their main above-water predators: birds and bats. Predators trying to capitalize on a sudden mayfly all-you-can-eat buffet are overwhelmed by the emergence of millions of insects. Some individuals make it through, and the species continues.
Oh, and the mass emergence is a sign that the Mississippi River is healthy. Hear that, all you who are caught in the swarms’ path? You should be grateful.
The NWS has a photo gallery documenting the invasion; check out some of the best (read: ickiest) below:
Lindsay Abrams is a staff writer at Salon, reporting on all things sustainable. Follow her on Twitter @readingirl, email firstname.lastname@example.org.More Lindsay Abrams.
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“Black Friday” Shoppers: Aggressive bargain hunters push through the front doors of the Boise Towne Square mall as they are opened at 1 a.m. Friday, Nov. 24, 2007, Boise, Idaho, USA
Suburban Sprawl: aerial view of landscape outside Miami, Florida, shows 13 golf courses amongst track homes on the edge of the Everglades.
Toxic Landscape: Aerial view of the tar sands region, where mining operations and tailings ponds are so vast they can be seen from outer space; Alberta, Canada
Ice Waterfall: In both the Arctic and Antarctic regions, ice is retreating. Melting water on icecap, North East Land, Svalbard, Norway
Satellite Dishes: The rooftops of Aleppo, Syria, one of the world’s oldest cities, are covered with satellite dishes, linking residents to a globalized consumer culture.
Child Brides: Tahani, 8, is seen with her husband Majed, 27, and her former classmate Ghada, 8, and her husband in Hajjah, Yemen, July 26, 2010.
Megalopolis: Shanghai, China, a sprawling megacity of 24 Million
Big Hole: The Mir Mine in Russia is the world’s largest diamond mine.
Clear-cut: Industrial forestry degrading public lands, Willamette National Forest, Oregon
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Oil Spill Fire: Aerial view of an oil fire following the 2010 Deepwater Horizon oil disaster, Gulf of Mexico
Airplane Contrails: Globalized transportation networks, especially commercial aviation, are a major contributor of air pollution and greenhouse gas emissions. Photo of contrails in the west London sky over the River Thames, London, England.
Fire: More frequent and more intense wildfires (such as this one in Colorado, USA) are another consequence of a warming planet.