Cold arctic air brings below freezing temperatures, sea smoke, and steam devils
Jan 21, 2025 10:10AM ● By Content Editor
Photo: Laura Durenberger-Grunow
By Laura Durenberger-Grunow - Boreal Community Media - Updated January 21, 2025. Originally posted January 17, 2024
Cold arctic air brings more than just below-freezing temperatures. Steam fog, frost smoke, sea mist, or as many people along the north shore call it, sea smoke, occurs when a very cold air mass drifts over "warm" water and forms fog. In recent instances, actual air temps have been well below zero (with the wind chill making it feel even colder), while the lake's water temperature has been hovering around 36 degrees Fahrenheit in the Cook County area.
If you're looking for a more official explanation of the process, the American Meteorological Society states that "No matter what the nature of the vapor source (warm water, industrial combustion exhaust, exhaled breath), its equilibrium vapor pressure is greater than that corresponding to the colder air; thus, the water vapor, upon becoming mixed with and cooled by the cold air, rapidly condenses. It should be noted that this mechanism never allows the fog to actually reach the vapor source."
But it's not just sea smoke that has been spotted in these cold temperatures. A unique arctic weather phenomenon spotted along the north shore is steam devils or steamnados. Conditions needed for steam devils are the same as for sea smoke: extremely cold air over a warmer body of water. In simplest terms, they can be thought of as mini fair weather waterspouts, which are whirling columns of air and water mist. As explained in this article from last year, when a Cook County resident spotted one near Lutsen, fair weather waterspouts are not tornadic (these are separate) and form starting at the water level and traveling up to a cloud. They are not typically associated with thunderstorms. Steam devils develop similarly but have a much more shallow "vertical depth" than waterspouts. Vertical depth is the distance between the surface (in this case, water) and a specific altitude, such as a point within a cloud of fog within the atmosphere.
You can view a recent video from Destination Duluth of a steam devil below.
For more information about sea smoke, visit the American Meteorological Society website here.
By Laura Durenberger-Grunow - Boreal Community Media - Updated January 21, 2025. Originally posted January 17, 2024
Cold arctic air brings more than just below-freezing temperatures. Steam fog, frost smoke, sea mist, or as many people along the north shore call it, sea smoke, occurs when a very cold air mass drifts over "warm" water and forms fog. In recent instances, actual air temps have been well below zero (with the wind chill making it feel even colder), while the lake's water temperature has been hovering around 36 degrees Fahrenheit in the Cook County area.
If you're looking for a more official explanation of the process, the American Meteorological Society states that "No matter what the nature of the vapor source (warm water, industrial combustion exhaust, exhaled breath), its equilibrium vapor pressure is greater than that corresponding to the colder air; thus, the water vapor, upon becoming mixed with and cooled by the cold air, rapidly condenses. It should be noted that this mechanism never allows the fog to actually reach the vapor source."
But it's not just sea smoke that has been spotted in these cold temperatures. A unique arctic weather phenomenon spotted along the north shore is steam devils or steamnados. Conditions needed for steam devils are the same as for sea smoke: extremely cold air over a warmer body of water. In simplest terms, they can be thought of as mini fair weather waterspouts, which are whirling columns of air and water mist. As explained in this article from last year, when a Cook County resident spotted one near Lutsen, fair weather waterspouts are not tornadic (these are separate) and form starting at the water level and traveling up to a cloud. They are not typically associated with thunderstorms. Steam devils develop similarly but have a much more shallow "vertical depth" than waterspouts. Vertical depth is the distance between the surface (in this case, water) and a specific altitude, such as a point within a cloud of fog within the atmosphere.
You can view a recent video from Destination Duluth of a steam devil below.
For more information about sea smoke, visit the American Meteorological Society website here.
