Steam devil refers to a weak and small whirlwind lingering over a water body or even on a wetland, which has sucked fog into the vortex and therefore making it visible. They are typically formed over the oceans or and large lakes when there is an outbreak of cold air when the water is still comparatively warm. Other relatively small steam devils could be formed over the geysers during warm weather due to the high temperatures in water.
Characteristics of a Steam Devil
Steam devils usually spin in a tornado-like direction of movement though not as strong or fast, with a few revolutions every minute, and sometimes none at all. Their usual shape is close to a small drinking fountain and are usually vertical, about 1600 feet high and can be as wide as 160 to 600 feet in diameter. Typically, the core of a steam devil is about 10% of its spinning column width and just like the core of a dust devil is clear, the center of a steam devil is clear at the core. Since steam devils are not common and their occurrence is short-lived, they last less than five minutes, while those forming over hot springs disintegrate within a few seconds. Steam devils are typically rare, though they are produced daily by the hot springs in Yellowstone Park. Studies on steam devils began in the 1970s, and they are slightly weaker compared to waterspouts, which are more like tornadoes over water.
Origin of the name
The name "steam devils" was coined by Lyons and Pease when they first reported the phenomena in 1972 following the observations made in January 1971 on Lake Michigan. At the time it was the coldest month in Wisconsin coupled with Lake Michigan which was ice-free, thereby creating a favorable condition for the formation of the steam devil. They named it steam devil in comparison to dust devils, which are typically common on land and are comparable both in structure and size. They also wanted to differentiate the steam devils waterspout, which is more powerful and their land equivalent is a tornado.
When and Where Do Steam Devils Occur?
Steam devils are most common on large water bodies such as lakes and oceans but can also happen on small lakes and above hot springs on rare occasions. There are instances when steam devils take place above wetlands when the cold air is present, and heat is produced as the sun heats the ground. The common areas where this happens are in the Great Lakes region which is a formation of a series of connected freshwater lakes found around the upper mid-east area of Northern America, along with the United States and Canadian border, where Saint Lawrence River connects them to the Atlantic Ocean. There is also the occurrence of small steam devils on some of the geysers and bigger hot springs in Yellowstone Park when layers of the steam hang above the pools, and winds start lifting them up into the fog.