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.
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.