National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

Lake Fly Hatch Seen on NWS Doppler Radar

The annual spring hatch of lake flies on Lake Winnebago was detected by the NWS Green Bay Doppler radar during the morning of May 8, 2009.  Lake flies, which look like big mosquitoes, hatch each spring around this time.  Department of Natural Resource officials report there are many millions of these flies that emerge from Lake Winnebago--potentially into the trillions.  Once hatched, the lake flies live for up to two weeks before dying off.

Radar image of lake flies on Lake Winnebago.  Click for larger image.  
^{Please credit National Weather Service-Green Bay.}

Animation from 7:05 am to 7:42 am CDT showing lake flies emerging from Lake Winnebago.  Click for larger animation.
^{Please credit National Weather Service-Green Bay.}