Sometimes the sand sings. It hums and groans as the wind rearranges it. Oſt en, the


sand spins and swirls, whipping across the landscape in mini tornadoes. At times, the sand is still, piled high in


towering dunes. But the sand of the Sahara is never still for long, for this is a place of constant movement and change. T e Sahara is the world’s largest hot desert.


It covers an enormous swath of land in North Africa. If the Sahara were a country, it would be the fi ſt h largest in the world. Eleven countries have parts of the Sahara within their borders.


A Changing Land Many people think of the Sahara as a dry and desolate place, unchanged for millions of years. Yet nothing could be further from the truth. T e Sahara is a dynamic place, shaped by the forces of weathering and erosion. Weathering—the breaking down of rock—


comes in several forms. Temperature extremes caused by the sizzling Saharan sun by day and frigid cold by night create a cycle for desert rocks. T ey expand and contract. Rocks split and break apart under these extremes. Powerful winds spin sand, dust, and small


rock particles in the air. T ese scrape and grind away at the landscape. Rare and sudden rain storms bring on fl ash fl oods that erode, or cause the movement, of sand, rocks, and stones. Over time, weathering and erosion create desert features such as sand dunes, tall mountains, rocky plateaus, shallow basins, and scrub-covered plains. Of all the types of landforms here, sand


dunes may be the most familiar. Sand dunes are oſt en found in ergs. Ergs are large areas of sand. In Morocco,


the golden sands of Erg Chebbi span an area of about 50 kilometers from north to south and about 10 kilometers from east to west. Ergs only make up about 20 percent of the


Sahara. T ey cover vast portions of Algeria and Libya as well as Mali and Nigeria.


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Although it is only one feature of the desert, the Sahara may be best known for sand dunes.


Other landforms are more common in the


Sahara, like the reg. A reg is a fl at plain that is covered with tightly packed, wind-scoured gravel. Regs are sometimes described as “desert pavement.” T ey make up 70 percent of the Sahara. T ey are the remains of ancient river and seabeds. Another common Sahara landform is called


a hamada. T is type of desert landscape has very little sand and is formed mostly of barren, rocky plateaus. Much of the Sahara is mountainous. T e


Hoggar Mountains in southern Algeria are red and rocky. T e snow-peaked Atlas Mountains sprawl across Morocco, Algeria, and Tunisia. An area of the Sahara located in Chad contains volcanic mountains.


FAST FACT:


Don’t make the mistake of saying “Sahara Desert.” That would mean: “Desert Desert.” Sahara is an


English pronunciation of the Arabic word for “desert.”


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