Sandstorms
Weather
and sandstorms
Pictures
Sandstorms can rapidly change the appearance of an area with the shifting and re-forming of dunes by the wind. Dust storms in arid regions can be formed when small, light dust particles are blown in to the air, often lifted by the strong winds at the leading edge of a cold front. In some drought prone areas, a 'dustbowl' effect can be caused by prolonged drought over a long period because of persistent failure of the rains, and often exacerbated by overgrazing.
Dust and Sandstorms
Sand and dust storms are natural events which occur widely around the world, in arid and semi- arid regions, temperate, tropical and sub-tropical latitudes. They are one of the more unpleasant weather phenomena and can be hazardous to transportation and navigation and for human health. Severe or prolonged dust and sand storms also result in major disasters. A dust storm which lasted for 5 hours near Jingchang, China caused 640 million yuan in economic damage over a wide area and injured and killed upwards of 300 people. In mid-March 1998, the Middle East was hit by choking sandstorms, claiming four lives, leaving 29 people injured, forcing the Suez canal, airports and seaports to close and bathing the region in an eerie yellow light.
The arid region around the Arabian Sea experiences the highest frequency of dust storms with over 30 per year occurring in the area joining Iran, Afghanistan and Pakistan. In Egypt, sandstorms -- called "khamsin (fifty)" for the number of days on which they can occur -- are a seasonal hazard and in 1997, 18 people died when that country was hit by the worst sandstorm in 30 years. Dust storms occur on a variety of spatial scales from mesoscale/regional to continental and remove large quantities of surface sediments and topsoil along with nutrients and seeds.
Timely early warnings of impending sand and dust storms are critical to preparedness for these, at times, disastrous events. National Meteorological Services in affected countries now prepare and issue such warnings when expected weather conditions favour their development. Longer-term mitigative measures are also being pursued such as the planting of trees and vegetation cover, modification of agricultural practices and public education initiatives.
For the future, efforts must continue to increase our understanding of duststorms and the factors which influence their development, movement and decay to improve our ability to provide early warnings of these events. In addition, longer term mitigative measures aimed at increasing awareness and reducing vulnerabiliy and exposure must continue to be pursued.
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