Issaouane Erg confined to basins. Sand in the Issaouane Erg, below the level of the sand dunes, has accumulated to a depth of 20 to 30 meters. It has barchan dunes as well as star dunes of 300 to 430 meters high. The presence of both barchan dunes (which form due to unidirectional winds) and star dunes (which form when winds from various directions deposit sand) "suggests that wind regimes have changed over time". NASA's "Earth Observatory" notes all three types of erg dunes are present in the photos of the Issaouane Erg taken from the International Space Station: stationary mega dunes,
Erg (tug) generators) through the fog and rain, when she was run down by a Norwegian freighter – a steamship named "Norelg" (See Convoy SC 94 for more information on this ship). The tug immediately began sinking and as a result, 19 men lost their lives. On July 19, the Royal Canadian Navy utilized the floating crane "Lord Kitchener" to raise the wreck of "Erg" so the bodies of the deceased could be recovered. Only 10 bodies were discovered and removed from the wreck. "Erg"s sinking was and still is considered one of the worst accidents to have taken place in the