CHICAGO _ Smoke on the water. It's not just a song lyric when it is hovering over Lake Michigan.
Called sea smoke or sea fog, this phenomenon happens when a mass of very cold air blows over warmer water. It's similar to what happens when a football player removes his helmet, and "smoke" appears above his head during a cold game.
National Weather Service Chicago meteorologist Ricky Castro says this phenomenon happens often during Chicago winters _ even when Lake Michigan is covered in ice, as in polar vortex-influenced winters. "When a cold air mass moves off the land and interacts with the ice cover, then the smoke effect will still occur," he said. "The temperature of the ice is still warmer than the air above it."
Castro says the process is aided by wind, "If winds were calm, then the effect might not be as dramatic."
