http://www.cbc.ca/news/canada/windsor/annual-fish-fly-hatch-on-lake-st-clair-picked-up-on-radar-1.3649661
'Tis the season for the annual fish fly hatch on Lake St. Clair and Lake Erie.
Every year, thousands of the winged aquatic insects emerge from local bodies of water, only to hover around lights, cling to windows and walls, mate and then die — all within about 48 hours.
This year, the hatch is so abundant, it's being captured every evening on radar in Detroit.
The National Weather Service tweeted a picture of the hatch June 18. The image shows dark blue patches, representing thousands of fish flies, over Lake St. Clair and the western edge of Lake Erie.