A dust storm, also called sandstorm, is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface. Fine particles are transported by saltation and suspension, a process that moves soil from one place and deposits it in another.
Drylands around North Africa and the Arabian peninsula are the main terrestrial sources of airborne dust. Poor management of the Earth's drylands, such as neglecting the fallow system, are increasing dust storm's size and frequency. This, in turn, changes both the local and global climate, and also impacts local economies.
The term sandstorm is used most often in the context of desert dust storms, especially in the Sahara Desert, or places where sand is a more prevalent soil type than dirt or rock. As the force of wind passing over loosely held particles increases, particles of sand first start to vibrate, then to move across the surface in a process called saltation. As they repeatedly strike the ground, they loosen and break off smaller particles of dust which then begin to travel in suspension.
In desert areas, dust and sand storms are most commonly caused by either thunderstorm outflows, or by strong pressure gradients which cause an increase in wind velocity over a wide area. The vertical extent of the dust or sand that is raised is largely determined by the stability of the atmosphere above the ground as well as by the weight of the particulates. In some cases, dust and sand may be confined to a relatively shallow layer by a low-lying temperature inversion.
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