Sea smoke is a meteorological event caused by the interaction of cool air and warm water. Often seen in coastal regions, sea smoke is sometimes known as advection or steam fog, and has a distinct appearance that can make a body of water appear to be smoking or steaming. Sea smoke frequently dissipates quickly, thanks to the warming action of the ocean on the frigid air.
When cold air, such as wind from the polar regions, reaches a relatively warm area of water, sea smoke can be created at the surface. Warm air contains more water vapor than cool air, and is lighter, which increases the rate at which it rises away from the surface. The naturally occurring warm air just above the water surface rises faster than the icy polar air above it, adding water vapor into the frigid layer. Since the cold air is unable to absorb most of the water vapor, the warm air condenses as it rises. The action of condensation is what allows sea smoke to become visible, just as warm breath becomes visible in the chilly air on a cold day.
Since sea smoke is created by air just above the water surface rising and condensing, it has a unique appearance that gives rise to its name. Instead of a low bank of fog, sea smoke takes the form of large plumes of gray or white air, rising from the surface of the water. Long vertical plumes of smoke can rise separately, especially in areas where wind speed is low, giving areas of water surface the look of smoldering lava fields. In higher wind areas, the smoke may merge into a thick fog layer, which may pose visibility hazards for ships.
Despite the potential for visibility issues, sea smoke rarely poses a serious hazard. Since the effect is caused by warm air rising through cool air, smoke will dissipate and vanish as the air temperature rises. As the rising warmth spreads through the colder air, more will be absorbed, leading to reduced condensation and the dissipation of the smoke. The smoke rarely condenses into extremely large banks, since the simple warming action of the rising air limits the amount of space that can be overtaken before it vanishes. Though sea smoke can occur over nearly any type of water, it is often found in the North Atlantic ocean, when drifts of Arctic air from the polar region passes over the somewhat warmer ocean areas.
