Photo above comes courtesy of my friend Al, who works for the Maine State Ferry Service. It's a cold winter morning on the way to Carver's Harbor on Vinalhaven Island in Maine's Penobscot Bay. You can see a stream of sea smoke off the starboard bow.
Sea smoke, advection fog, or steam fog, is an interesting physical phenomenon caused by cold air advection over warmer water. It's a type of fog that requires a perfect set of conditions. The nearest comparison would be the strange mist you sometimes see on the surface of your hot coffee, before you add the cream and sugar. Take a look at it next time you pour yourself a cup. Clouds of tiny water droplets are racing across the surface.
What makes sea smoke and the mist on your coffee different than other types of fog and mist is the size of the droplets. In sea smoke and the mist in your coffee, all the droplets are of uniform size and kinetic energy. The bigger, slower droplets fall back into liquid, and the smaller, more kinetic droplets, evaporate completely.
Sea smoke and the steam fog on your hot coffee are the same phenomenon.