Cold Enough Yet? The science behind sea smoke BY CATHERINE SCHMITT | PHOTOS BY JAMIE BLOOMQUIST

IVING THROUGH THE MAINE the liquid phase, a process called subli­ greater the chance that sea smoke will winter comes with its own rewards: mation. The principle behind all these form and persist long enough to be seen. seeing the lay of land and sky forms of mist is the same—the differ­ It rises from the surface, mixing and Lthrough bare trees, walking across ence in temperature between two turbulent, in rotating columns, converg­ frozen swamps and bogs, jigging for spheres. ing swirling devils, and stratified drifts. smelt and tomcod beneath the ice. How cold does it have to be for sea Like your breath on a cold day, the sea But sometimes the weight of winter smoke to form? In the Gulf of Maine, the exhales dragon-tongues of frost. is heavy. When the landscape seems winter sea-surface temperature hovers in The National Weather Service can locked in place and time, liquid tidewa­ the 30s, according to John Cannon of the detect sea smoke from visibility sensors ters, bays, and harbors offer relief to eyes National Weather Service office in Gray, on the Northeastern Regional Associa­ that yearn for movement and contrast. At Maine. “We observe sea smoke over tion of Coastal and Ocean Observing the sea’s edge, the tide still comes and Systems buoys (NERACOOS), which goes, waves still crash and sing their are located two to three miles offshore; slushy songs, sea ducks ride the chilly surf. It rises from the surface, go to www.neracoos.org/realtime_map If the air is still and cold enough, for links to the buoys. Usually, said Can­ great wisps of sea smoke hover and drift mixing and turbulent, in non, by the time air masses reach the above the water surface. That “smoke” buoy the air has warmed to the point actually is water vapor that forms when rotating columns, converging where sea smoke is less likely to form. really cold air moves over relatively But last winter was colder than most, warmer water and the thin boundary swirling devils, and stratified and the sea smoke could be seen from layer of warm air just above the surface. the buoys, close to shore, even at beach­ When the evaporating water rises, the drifts. Like your breath on a es. cold air can only hold so much moisture, “Most of the time when it is cold, forcing the liquid to condense into fog. cold day, the sea exhales the winds are blowing out of the north­ Clouds rise like smoke from the sea’s west and offshore, carrying any vapor surface, dispersing and reforming, turn­ dragon-tongues of frost. away from beaches” said Cannon. ing bays and coves into ephemeral caul­ Eventually, the air soaks up warmth drons of submarine fire. from the sea, the winds pick up, and the North Atlantic fishermen called it coastal waters when the air temperature smoke disperses. white frost or black frost. Common in is below 10 degrees, and definitely when Cannon also noted that during last polar regions (where it is called Arctic it’s below zero,” he said. winter’s record-setting cold periods, sea smoke), it can form over any body of It takes time for the cold to wring freezing spray built up thick coats of ice water if conditions are right. It also is the moisture out of the boundary layer on vessels. The exceptionally frigid win­ known as steam fog, especially when it of air above the water. Sometimes the ter prompted the National Weather occurs over freshwater lakes and rivers, wind blows the cold air away before the Service to reinstate their program of although the phenomenon really is the sea can smoke. The colder the air, the issuing freezing spray advisories for opposite of fog, which occurs when greater the temperature difference coastal waters. ✮ warm air moves over cold water. A sim­ between the air and the sea, and the faster ilar mist occurs when warm sun hits cold and more prolific the condensation. Catherine Schmitt is Communications ice, and the solid water goes directly to Therefore, the colder the temperature Coordinator for the Maine Sea Grant its vapor form without passing through outside and the quieter the wind, the College Program at the University of Maine.

64 Reprinted with permission of MAINE BOATS, HOMES & HARBORS | WINTER 2015 | Issue 132 You know it’s really cold out when you see sea smoke, which usually only occurs when the air temperature is below 10 degrees Fahrenheit. Photographer Jamie Bloomquist took these shots in Camden Harbor on January 24, 2011.