Polar Vortex Causes Chicago River To ‘Smoke’

In a month full of strange and record-breaking weather events, you can add "smoking Chicago River" to the list of oddities we're experiencing.

Aerial views of the Chicago area reveal a large portion of the river is covered in chunks of ice and giving off swirling sea smoke, also known as "steam fog" when it occurs over freshwater lakes or rivers.

From Fox News:

"That 'smoke' actually is water vapor that forms when really cold air moves over relatively warmer water and the thin boundary layer of warm air just above the surface," Sea Grant at the University of Maine previously explained in a paper. "When the evaporating water rises, the cold air can only hold so much moisture, forcing the liquid to condense into fog."