John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
“Terrifying and beautiful at the same time,” reports one witness.
If the ancient wind gods whipped up an old-fashioned reel mower and drove it over humanity, it might look like the foggy, spinning apparition that recently dominated the Michigan skyline.
Multiple people on the eastern coast of Lake Michigan, and particularly at the Sleeping Bear Dunes National Lakeshore, witnessed the huge roll cloud this weekend as it silently gusted over the region. “Terrifying and beautiful at the same time,” reports one woman. “I would probably have been running and snapping pictures as it looks like a giant tornado.”
Well, kind of: Push a giant tornado onto its side and give it a kick and you’d get a roll cloud, though without all the roof-ripping violence of a twister. This billowing spinner is, according to NOAA, a “low, horizontal tube-shaped arcus cloud associated with a thunderstorm gust front (or sometimes with a cold front).” They rotate on a horizontal axis, remain “relatively rare,” and are “completely detached from the thunderstorm base or other cloud features, thus differentiating them from the more familiar shelf clouds.”
Here are a few more shots of the beast: