Grand Erg Occidental Grand Erg Occidental The Grand Erg Occidental (, al-ʿIrq al-Gharbī al-Kabīr), (also known as the Western Sand Sea) is the second largest erg in northern Algeria after the Grand Erg Oriental. It covers an area of approximately . The sand dunes in the erg are formed by the wind, and can be up to high. Certain crescent-shaped dunes, known as barchans, are actually mobile; the wind can push these dunes as much as 20 to 30 m (65-100 ft) in one year. It is a desert natural region that receives less than 50 mm (1,96 in) of rainfall per year.
Erg Iguidi of seasonal vegetation with grasses and shrubs and in the summer the desert is used as a pasturage area. The Erg Iguidi supports a population of slender-horned gazelle. Erg Iguidi The Erg Iguidi (), is a large erg in the area of Tindouf in southwestern Algeria extending into northern Mali and Mauritania. The Erg Iguidi is a sandy desert with a clear pattern of narrow linear dunes stretching for a length of 400 km. Part of the greater Sahara, it is located in its northwestern region and is characterized by Harmattan withering winds. The highest point is 540 m. Compared