Coastal Processes FAQ - Sometimes it looks like clouds of smoke are coming off of the ocean. What is this called and why does it happen?

What you observed is called sea smoke.

These smoky-looking plumes rising from the ocean surface can be seen when still cold air overruns the warm moist air at the sea surface. Because the surface air is so much warmer than the cold air above it, the moisture in the rising warm air quickly condenses into small water droplets (like seeing your breath on a cold day). This phenomenon is often observed in colder climates – for example in the Arctic, Antarctic, and along the coast of Maine. Autumn is the season when sea smoke is most typically observed, as cold blasts of polar air masses blow over warm Atlantic waters.

A more technical explanation of sea smoke is provided in the glossary of Arctic Climatology and Meteorology: Sea smoke - Evaporation fog or steam fog which is formed when water vapor is added to air which is much colder than the vapor's source; most commonly, when very cold air drifts across relatively warm water.

The American Meteorological Society provides this definition for sea smoke:

sea smoke — (Also antarctic sea smoke, arctic sea smoke, arctic smoke.) Same as steam fog, but often specifically applied to steam fog rising from small areas of open water within sea ice in the Arctic or Antarctic region.