Dust devil: Encyclopedia - Dust devil

Dust devil

A dust devil or whirlwind is either a large rotating updraft, anywhere from 1000 meters high or more and tens of meters in diameter, to a small vortex a few meters high. In Australia, they are commonly known as willy willies, from an Aboriginal word.

Dust devil - Larger dust devils

The larger dust devils are often observed in times of atmospheric turbulence, especially common in the San Luis Valley of Colorado. Depending on the classification system used they may be considered weak tornados or landspouts. They are visible in the Great Basin and eastward to El Paso, for example. They are distinct from the common dust storms of this area, because they resemble small tornados. Due to this they are best viewed from a distance, and at a height (say, from a mountaintop). These whirlwinds are not extremely hazardous to biological organisms, but machines and electronics can suffer many severe malfunctions through repeated exposure to dust devil activity, including but not limited to increased wear from dust and short circuits or other physical damage caused by electrical arcing.

Dust devil - Smaller dust devils

The smaller dust devils reach only a few meters or tens of meters in height, forming commonly in hot dry weather, most observably in fields or dusty flats, where the soil makes them visible, and which may be shorter-lived.

Dust devil - Electrical activities

It was recently found that even small dust devils (on Earth) can produce radio noise and electrical fields greater than 10,000 volts per meter.[1]

Dust devil - Martian dust devils

Dust devils also occur on Mars, and were first photographed by the Viking orbiters in the 1970s. In 1997, the Mars Pathfinder lander detected a dust devil passing over it.[2] Martian dust devils can be up to fifty times as wide and ten times as high as terrestrial dust devils, and large ones may pose a threat to terrestrial technology sent to Mars.[3]

Mission members monitoring the Spirit rover on Mars reported March 12, 2005 that a lucky encounter with a dust devil has cleaned the solar panels of that robot. Power levels have dramatically increased and daily science work is anticipated to be expanded. (space.com) A similar phenomenon (solar panels mysteriously cleaned of accumulated dust) had previously been observed with the Opportunity rover, and dust devils had also been suspected as the cause.

A large-scale cyclone has also been observed on Mars.

External links

• Australian Dust Devil Photos
• Dancing with the Devils Video
• Dust Devil Imaged by Spirit Rover on Mars
• Japanese Dust Devil Video
• Matador Dust Devil Project
• More pictures of Martian dust devils from Spirit

Category: Winds

Adapted from the Wikipedia article "Dust devil", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki