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 Chech Erg Chech The Erg Chech (), is a large erg in southwestern Algeria and northern Mali. It is an almost uninhabited part of the greater Sahara Desert, an inhospitable desert region with long, extremely hot summers and short, very warm winters. The Erg Chech is a vast sandy expanse including compound and complex linear and star dunes. The mean elevation of the Erg Chech is just above 300 m, slightly lower than the neighboring Erg Iguidi stretching to the north. The barren plain of the Tanezrouft is located to the southeast. One of the localities of the commune of Akabli