CLEVELAND - Ohioan Wendy Akagi was looking west from her home along the Lake Erie shoreline and noticed something she'd never seen before. It was a city. Yes, a city had magically appeared on the horizon.
"When we look west we see a skyline that we have never seen before!" She wrote on Facebook. "I know the water level is low but it looks like a new land has just popped up... what is this????"
Normally, you can't see the Canadian Shore from downtown Cleveland. It's more than 50 miles north of us and the Earth's curvature keeps anything that far away tucked out of sight.
Except for this week. A rare weather phenomenon allowed residents all along Lake Erie's south shore to see our Lake's north shore. You could see Canada from here Wednesday and Thursday.
The phenomenon is called super refraction. It's a bending of light rays downward toward the Earth's surface. It is caused by changes in the density of the air with height. An impressive temperature inversion over Lake Erie caused the sun light to bend downward enough, so that distant objects not normally seen could now be seen with the naked eye.
Here's what happened: The lake is still very cold. Any air over that chilly water is instantly cooled. But the air over the nearby land and above that thin, chilly marine layer has been warmer than normal all week. We've seen highs in the 70s. That warm air flows over top of the shallow cold air over Lake Erie, effectively creating a lid or "cap." That thin layer of cold air is denser than the warm air above it and beside it. This "lid" allows light rays to bounce off of it and get reflected back down towards the Earth's surface. These BENT light rays allow us the ability to see what's reflected in the light at much farther distances than normal. Even objects that are beyond the horizon. Oh, Canada!
The city Wendy saw? Most likely suburbs around Detroit, Michigan.