Dust storm

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A dust storm (or sandstorm in some contexts) is a meteorological phenomenon common in dry, arid and semi-arid regions. Such a storm is usually the result of convection currents created by intense heating of the ground. These currents then carry sand over large distances.

1 Origins
2 Effects
3 On other planets
4 Notable dust storms
5 See also
6 External links

[edit] Origins

Usually, a dust storm is a result of convection currents forming from hot ground. These currents can create winds that blow up to 120 km/h. These storms are often very large and can move whole sand dunes. Dust storms can carry large amounts of dust, so much so that the leading edge of one can appear as a solid wall of dust as much as 1,525 m high. Dust storms often come off the Sahara Desert with the global trade winds. These are also known as a simoom or simoon (sîmūm, sîmūn). The haboob (həbūb) is a sandstorm prevalent in the region of Sudan around Khartoum. Drought and wind contribute to the emergence of dust storms, as do poor farming and grazing practices by exposing the dust and sand to the wind.

[edit] Effects

Dust storms often interferes with travel, sometimes obliterating roads in flat, dry regions such as those of the western United States. For instance, on November 29, 1991 a convective dust storm formed over Interstate 5 in the San Joaquin Valley, California. The storm picked up dust in a suspension with winds at speeds of over 120 km/h. Visibility was reduced to less than half a car's length, causing a pile-up accident involving 164 cars, killing 17 and injuring 151.

Dust storms can also carry away valuable topsoil, while depositing it in places where it is not wanted.

The simoom (sîmūm, sîmūn) contributes largely to the atmospheric dust over Europe; evidence of the dust from simoon winds has also been found on the seafloor at considerable distances from shore. The dust picked up in such a storm can be carried thousands of kilometers: Sahara dust storms influence plankton growth in the western Atlantic Ocean and, according to some scientists, are an important source of scarce minerals for the plants of the Amazon rainforest.

Dust storms can often be observed from satellite photos, the use of which is highly valuable in forecasting; of particular use are the NASA imaging devices MODIS and SeaWIFS.

Image:Sandstorm.jpg

Dust storm approaching Stratford, Texas, in 1935.

[edit] On other planets

A massive global dust storm raging on Mars in 2001.

Dust storms are also known to occur on a massive scale on the planet Mars. Storms on Mars last longer, and cover larger areas, than on Earth; some of these storms cover the entire planet and last for hundreds of days.

[edit] Notable dust storms

One that occurred near Tucson, Arizona, USA on July 16, 1971 was extensively documented by meteorologists.
On the afternoon of February 8, 1983, a huge dust storm originating in the Mallee region of Victoria, Australia covered Melbourne.