Editor’s note: Brooklin author/photographer Richard J. Leighton creates the popular “In the Right Place” posts online about life and nature in Maine. He shares a post the second Thursday of each month in The Ellsworth American.
January here on the Downeast coast usually is the best time to witness a spectacle that can be wonderful to watch from the shore and dangerous to navigate through while at sea. It’s usually in the form of a strange cauldron — an ice-cold one — filled with smoke, like Brooklin’s Naskeag Harbor shown in the accompanying image.
What is that smoke? It’s “sea smoke,” a special form of fog that rises from the sea instead of descending to it. It happens only when conditions are right: usually when the air is below 10 degrees F and very cold winds are blowing slowly over warmer (but still cold) waters.
That’s when the rising air just above the sea’s surface gets rapidly colder to the point that it can’t hold all its water vapor. Some vapor condenses and evaporates out as smoke, the way the air above hot coffee or soup does. Then comes the beautiful part: the winds play with the smoke as it rises, creating a storybook world of mysterious swirling wisps and clouds that sometimes are dense curtains, sometimes thin veils.
Although this dramatic event usually is called sea smoke on our coast, it’s also known by many other names, including Arctic smoke; frost smoke; water smoke; steam fog; cold air advection fog; warm water fog, and evaporation fog. Some fishermen reportedly differentiate between “black frost” and “white frost” sea smoke — black when they can’t see through it and white when they can see ahead because the fog is low or thin.
The dangerous part about sea smoke has to do with ice formation (“accretion”) on ships that can jeopardize them, especially fishing trawlers that stay at sea for days in northern latitudes. Determining how this icing occurs, developing forecasting models for it and issuing safety guides about it has become an increasingly significant part of the activities of the World Meteorological Organization and others.
The most dangerous reported cause of ships “icing up” and foundering is very cold sea spray that arises as the vessel plows through the water in frigid winds. But, ice accretion from swirling sea smoke has been reported by the WPO as a contributing factor in some vessel losses and the main factor in at least one loss.
Think about that the next time you’re allured by the beauty of sea smoke.