A severe weather outbreak in the Chicago area caused extensive wind damage and some localized flooding on Monday afternoon, but a unique phenomenon captured on video led some to question whether a waterspout formed in the city itself.
An NBC 5 viewer sent in video from the storm that appeared to show what looked like a waterspout dissipating on the Chicago River near the base of Trump Tower and the Wabash Avenue bridge on Monday afternoon:
While the spinning column of wind and water looked like the beginning or the end of a waterspout, the NBC 5 Storm Team says that it didn’t quite fit that definition.
According to the National Oceanic and Atmospheric Administration’s online glossary, a waterspout is defined as a “small, relatively weak rotating column of air over water that forms beneath a Cb or towering cumulus cloud.”
The phenomenon that occurred over the Chicago River occurred when wind gusts rose to nearly 60 miles per hour in the downtown area.
That portion of Chicago where the vortex occurred has dozens of tall buildings, which helps to accelerate the flow of air as it passes between the structures, according to NBC 5 Storm Team Meteorologist Paul Deanno.
Local
The Chicago River, effectively, is the largest “opening” between the buildings, which causes wind that’s moving in various directions to converge, causing short-lived vortices at water-level.
The column of rotating wind became visible because of a combination of rainfall and river water, but since it did not originate from the clouds, it is not technically considered to be a “waterspout,” according to our experts.
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