Strong winds blowing over loose soil or sand causes sandstorms. During a sandstorm, so much material is picked up by the winds that visibility is greatly reduced. Heating of the air over the desert causes instability in the lower atmosphere, making sandstorms more frequent.
A sandstorm can last from several hours to a full day. The sand moving within a sandstorm can clog nearly anything mechanical. Breathing is also a problem, and masks are a necessary precaution during a sandstorm. Most sandstorms affect only one to three miles, so air travel is usually not a problem.
There are two types of sandstorms. The first, called a "haboob," an Arabic word for blowing dust, results from strong winds of a severe thunderstorm. The second is caused by the curving of the jet stream which brings strong winds to the ground. Most Americans are familiar with this type, according to Texas A&M University Department of Atmospheric Sciences.
Some of the worst sandstorms form in China and Mongolia. The sand in the air is so dense it changes the color of the rain, creating the appearance of yellow rain falling from the sky. Sandstorms can grow large enough to be seen from space, and on Aug. 24, 2010, the NASA Aqua satellite captured an image of a widespread sandstorm that covered parts of Afghanistan and Pakistan.