A Sandstorm is basically a strong dry wind which blows over the semi-arid and arid regions. They raise and carry along with them clouds of dust or sand and are often so dense that they obscure the sun and reduce the visibility to zero. The particles of sand or dust are transported by saltation and suspension, a process through which the particles are moved from one place and are deposited in another. The Sandstorms are capable enough to modify or change the local and global climate. They are seen as solid walls of sand that are up to 5000 ft high. It is also believed that Sandstorms are capable of carrying infectious diseases.
Initially, when the force of wind passing over the loose particles increase, the particles of dust or sand start to vibrate, eventually leaping. Repeatedly as they strike the ground, they break off into smaller particles of dust which further begins to travel in suspension. The smallest particles begin to suspend and eventually increasing the population of dust grains which move by a range of process – suspension, saltation and creep. The saltating sand then acquires a negative charge which in turn loosens more sand particles which then begin saltating. Due to arid and drought conditions, the particles become loosely held. In desert areas, the sand and dust storms are often caused due to thunderstorm outflows or are caused due to strong pressure gradients which in turn cause an increase in speed of the wind. It is believed that wind and drought contribute to the emergence of Sandstorms, so do poor farming and other grazing practices which expose dust and sand to wind. Dryland farming is one of the farming techniques which contribute to the emergence of Sandstorms.
Sandstorms usually occur in deserts and in semi-arid and arid regions which are largely covered by sand. The plants and its roots help the sand stay in place, so the areas covered with large amount of plant life do not get affected by Sandstorms. Mostly majority of the Sandstorms occur in the Sahara and in the Arabian Peninsula. But it is believed that Sandstorms can occur anywhere in the world where a dry weather and sandy topsoil exist. They can even occur in areas which are not dry, but are experiencing dry weather. The countries which are associated with Sandstorms are Algeria, Afghanistan, Bahrain, China, Egypt, Iran, Iraq, Saudi Arabia, Syria, Sudan, United Arab Emirates, and Uzbekistan.
For the people living in semi-arid and arid regions, Sandstorms are part of their everyday life. However, Sandstorms have shown to increase the rate of diseases being spread across the world. Virus spores from the ground are blown away into the atmosphere by the storms. It is believed that the prolonged unprotected exposure in a Sandstorm can cause silicosis, which is an incurable condition that can lead to lung cancer. There are also higher chances of keratoconjunctivitis sicca (dry eyes), which if not treated immediately can lead to blindness. Sandstorms also affect the agricultural productivity as during a storm the organic matter and nutrient-rich particles are moved; eventually affecting the young crop plants. The other effects of Sandstorms lead to reduced visibility, which affect road and aircraft transportation, reduced sunlight, high level of dust and other ill effects on human health.