The Sudans Nile within the Sudans has no significant tributaries. The amount of rainfall increases towards the south. In the north there is the very dry Nubian Desert; in the south there are swamps and rainforest. The Sudans’s rainy season lasts for about three months (July to September) in the north, and up to six months (June to November) in the south. The dry regions are plagued by sandstorms, known as haboob, which can completely block out the sun. In the northern and western semi-desert areas, people rely on the scant rainfall for basic agriculture and many are nomadic, travelling with their
Kalahari Desert climate is drier, it becomes a true semi-desert with ground not entirely covered by vegetation: "open" as opposed to "closed" vegetation. Examples include the north of the ZF Mgcawu District Municipality, itself in the north of South Africa, and the Keetmanshoop Rural in the southeast of Namibia. In the north and east, there are dry forests covering an area of over 300,000 km in which Rhodesian teak and several species of acacia are prominent. These regions are termed Kalahari Acacia-Baikiaea woodlands AT0709. Outside the Kalahari "desert", but in the Kalahari basin, a halophytic vegetation to the north is adapted to