A picture of a shelf cloud moving through downtown Chicago courtesy of Earthcam.
A picture of a shelf cloud moving through downtown Chicago courtesy of EarthCam.
  • An imposing, ominous shelf cloud was spotted in the skies above Chicago. 
  • The cloud is a sign of severe thunderstorms and you should take shelter if one is coming your way.
  • Video shows the cloud moving through the city, bringing strong winds up to 60 mph with it.

At first glance, the shelf cloud that passed through the skies of Chicago on Wednesday morning looked like something out of "Independence Day." But don't worry — this ominous-looking formation isn't signaling the end of the world.