This page contains a Flash digital edition of a book.
Wind Power T e Sahara is a vast landscape, fi lled with many landforms. Yet there is one force that aff ects them all: wind. T e Arabic name for a wild, sand-laden

wind is haboob. Other Saharan winds also have their own special names. Khamsin is an Arabic word meaning “50 days.” T is wind sweeps across the desert from March through May, choking the air with sand. T e name of the dust-ladened wind harmattan comes from a word in the West African language, Twi. It means “to tear your breath apart.” T e direction and strength of the relentless

wind shapes the Sahara every day. Oſt en winds coming from the northeast churn at hurricane speeds. T ey give rise to severe sandstorms and dust devils. During sandstorms, the wind stirs up millions of grains of sand. At high speeds, wind-blown sand can strip the paint off of cars. T e sand doesn’t always stay in the Sahara.

Giant sandstorms—oſt en larger than Spain— routinely blow all the way across the Atlantic, reaching South America and the United States.

Taking Shape In the Sahara, these forceful winds not only change the shape of a sand dune, they can change its position, too. As the wind blows, it carries sand up one side of the dune and over the top. T e sand rolls down on the other side. T is

constant motion causes a shiſt . In this way, a massive dune can slowly travel across the desert. Some of the largest sand dunes move several meters every year. Wind can create distinct patterns and styles

of sand dunes. A barchan dune, for example, is crescent shaped. It seems to have horns that point downwind. T ese dunes are formed by winds that have blown from the same direction for a long period of time. Seif dunes have long, straight forms and

may extend for kilometers. T ey are formed by winds that blow from two directions. A star dune has a central pyramid-shaped

mound with radiating arms. Star dunes form in areas with large amounts of sand, with winds that blow from several directions.

A powerful sandstorm forms a wall of sand that whips across the landscape.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24