Mayfly hatch visible on doppler radar

You know it’s getting bad when mayflies are visible on Doppler radar.

Imagine what the forecasters on duty thought when they peered at the Doppler screen last Saturday evening at the La Crosse NWS. Shades of bright pink showed up over the Mississippi River. There were no storms in the area, so what were the radar returns?

Mayflies. Yup. Mayflies.

1 a bug_may2910a.png

A mayfly hatch along the Mississippi River was caught on Doppler radar out of NWS La Crosse Saturday evening. The radar view above shows an image at 9:13 p.m. CDT on Saturday, May 29, 2010. The bugs are showing up as bright pink, purple, and white colors along the Mississippi River mainly south of La Crosse, WI. After the bugs hatch off the water and river areas, they are caught in the south-southeast winds while airborne for about 10-20 minutes.

As the mayflies hatched on the Mississippi, the dense swarms reflected the radar beam back toward the Doppler receiver. The radar was in the very sensitive “clear air mode” which results in greater sensitivity and shows things like dust, birds, and well…mayflies.

Who knew?


  • Steven Hepokoski

    There 15 minutes of fame is, in their case, a pretty significant percentage of their lives.

  • Chris B. Critter

    In central Texas, one can see bats leaving their roosting places (caves) when the radars there are in clear-air mode.

  • Tom

    I LOVE to hear this! Each year around the 4th of July we take a lazy trip down the Mississippi to spend a few days sailing on Lake Pepin. A few years ago the Mayflies were thick EVEYWHERE between Prescott Wisconsin on south. This year, if they are hatching this early, it means they will be gone, gone, gone by the time we make our trip. THIS IS GREAT NEWS!

  • Karl

    heh… think this is bad you should see a scottish midge swarm rise xD

  • Blake

    A hell of a lot better than being a mosquito swarm!!! Plus! It makes the fish happy!

  • Blake

    A heck of a lot better than being a mosquito swarm!!! Plus! It keeps the fish happy!