by MJ Logan

Created on: November 07, 2008

What Do Steam Devils Do?

The ethereal steam devil is a rare and beautiful atmospheric event. Generally occurring in late fall or early winter, they appear for scant moments before seemingly vanishing into thin air.

Steam devils belong to the same class of cyclonic weather events as tornadoes, hurricanes, dust devils and water spouts, although they have much less energy and cause no damage. In order to form, conditions must be exactly right.; a cold mass of air over a body of much warmer water in conjunction with strong winds.

The process begins with water evaporating and rising into the cold air. Within a few feet, the water vapor condenses in the colder air, forming steam. The tiny water droplets continue to rise and the wind begins to push the steam into a gently turning vortex. The column of steam continues to rise and swirl upwards since it is warmer than the surrounding air.

In effect, steam devils do exactly what we all learned in grade school about the formation of clouds. Water evaporates, turning into a gas from its liquid state and the warm gas rises through the colder air. When the air is cold enough, it reforms into tiny water droplets and we see the end result as clouds. A steam devil is just this process. However, because of the weather conditions, we get to see the actual process taking place.

Steam devils have been observed over Lake Superior rising as high as fifteen hundred feet, going from the surface of the lake right up to the bottom of the clouds. This weather phenomenon gives us a chance to see science in action; the forming of clouds that later will produce rain or snow.

The steam devil forms seemingly out of nothing and within a few seconds or a few minutes, vanishes into nothing. If you see one, keep watching. The conditions are right and you might just see another. Of course, if you have a camera, take pictures.

If the winds are not so strong and the temperature difference between the air and the water is not so great, fog forming on the lake's surface may form into fingers and drift upwards. Light winds will swirl these fingers into short lived vortices that twirl skyward a short ways and dissipate into the cooler, drier air. The effect is both beautiful and amazing; many tiny, dancing, whirling figures forming and disappearing in a symphony created by the weather.

Steam devils may be the source of legends about lake monsters and lake serpents. Seeing one surely evokes the feeling you are watching a great ghostly spirit swirl its way gently to the sky. These amazing and beautiful oddities are hardly dangerous, however. They lack the energy to do more than carry the condensation from the lake skyward.

Good pictures of very tall steam devils can be seen at the University of Minnesota site below.

Sources:
Times Online
University of Minnesota Climatology Department.

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