So-called “steam devils” are named loosely, and somewhat inaccurately, after their dust-devil cousins. This isn’t steam, however, nor smoke (contrary to the nickname “sea smoke” for this kind of overwater fog formation). Similarly to dust devils, steam devils form over a water body that is much warmer than the air above, but with cloud (fog) condensation to mark their location, instead of dust tubes. This fog is convective: warmer, less-dense parcels rising through cold surrounding air, in a shallow layer. Steam devils are harmless, and can last anywhere from a few seconds (as with these) to several minutes for exceptionally large, tall, well-organized ones.
