On especially cold days like the last few, the air temperature is well below the temperature of the ocean. The differential between the two temperatures causes the water to steam, creating a fog that swirls across the surface of the water. It’s a beautiful thing to see, even if you don’t want to linger outside too long.
Similar swirls can be seen on the highway in extreme cold after a snowstorm. It’s caused when the snow that’s accumulated on cars and trucks breaks off and crashes onto the road surface (and hopefully not your windshield) and this snow is cast about by the wind currents of high speed traffic. This is beautiful for all the wrong reasons (Clean your cars off people!).
Sea smoke has another couple of interesting names. Steam fog, which is a great name for a beer, and frost smoke. But we call it sea smoke around here. When you see it, you know it’s bloody cold outside.