An intense sandstorm or duststorm caused by strong winds, with sand and/or dust often lofted to heights as high as 1500 m (~5000 ft), resulting in a “wall of dust” along the leading edge of the haboob that can be visually stunning. There is commonly a rapid and significant reduction in visibility and an increase in wind speed following the passage of the leading edge of a haboob, which can last for tens of minutes to a few hours. Haboobs are often caused by an atmospheric gravity or density current, such as thunderstorm outflow, but can also occur as a result of strong synoptic gradient winds, such as following a dryline or dry frontal passage. When a haboob is caused by a strong density current, the leading edge wall of dust roughly conforms to the shape of the associated density current head. Haboobs occur fairly regularly in the arid and semiarid regions of the world and can occur in any dry region. Sometimes they deposit enormous quantities of sand and/or dust.
Idso, S. B., R. S. Ingram, and J. M. Pritchard, 1972: An American haboob. Bull. Amer. Meteor. Soc., 53, 930–935, doi:10.1175/1520-0477(1972)053<0930:AAH>2.0.CO;2. 
Sutton, L. J. 1925: Haboobs. Quart. J. Roy. Meteor. Soc., 51, 25–30, doi:10.1002/qj.49705121305. 
term edited 8 June 2016