Terrain

Angola has three principal natural regions: the coastal lowland, characterized by low plains and terraces; hills and mountains, rising inland from the coast into a great escarpment; and an area of high plains, called the high plateau (planalto), which extends eastward from the escarpment.

The coastal lowland rises from the sea in a series of low terraces. This region varies in width from about 25 kilometers near Benguela to more than 150 kilometers in the Cuanza River Valley just south of Angola's capital, Luanda, and is markedly different from Angola's highland mass. The Atlantic Ocean's cold, northwardflowing Benguela Current substantially reduces precipitation along the coast, making the region relatively arid or nearly so south of Benguela (where it forms the northern extension of the Namib Desert), and quite dry even in its northern reaches. Even where, as around Luanda, the average annual rainfall may be as much as fifty centimeters, it is not uncommon for the rains to fail. Given this pattern of precipitation, the far south is marked by sand dunes, which give way to dry scrub along the middle coast. Portions of the northern coastal plain are covered by thick brush.

The belt of hills and mountains parallels the coast at distances ranging from 20 kilometers to 100 kilometers inland. The Cuanza River divides the zone into two parts. The northern part rises gradually from the coastal zone to an average elevation of 500 meters, with crests as high as 1,000 meters to 1,800 meters. South of the Cuanza River, the hills rise sharply from the coastal lowlands and form a high escarpment, extending from a point east of Luanda and running south through Namibia. The escarpment reaches 2,400 meters at its highest point, southeast of the town of Sumbe, and is steepest in the far south in the Serra da Chela mountain range.

The high plateau lies to the east of the hills and mountains and dominates Angola's terrain. The surface of the plateau is typically flat or rolling, but parts of the Benguela Plateau and the Humpata Highland area of the Huíla Plateau in the south reach heights of 2,500 meters and more. The Malanje Plateau to the north rarely exceeds 1,000 meters in height. The Benguela Plateau and the coastal area in the immediate environs of Benguela and Lobito, the Bié Plateau, the Malanje Plateau, and a small section of the Huíla Plateau near the town of Lubango have long been among the most densely settled areas in Angola.

Drainage

Most of the country's many rivers originate in central Angola, but their patterns of flow are diverse and their ultimate outlets varied. A number of rivers flow in a more or less westerly course to the Atlantic Ocean, providing water for irrigation in the dry coastal strip and the potential for hydroelectric power, only some of which had been realized by 1988. Two of Angola's most important rivers, the Cuanza and the Cunene, take a more indirect route to the Atlantic, the Cuanza flowing north and the Cunene flowing south before turning west. The Cuanza is the only river wholly within Angola that is navigable--for nearly 200 kilometers from its mouth- -by boats of commercially or militarily significant size. The Congo River, whose mouth and western end form a small portion of Angola's northern border with Zaire, is also navigable. North of the Lunda Divide a number of important tributaries of the Congo River flow north to join it, draining Angola's northeast quadrant. South of the divide some rivers flow into the Zambezi River and thence to the Indian Ocean, others to the Okavango River (as the Cubango River is called along the border with Namibia and in Botswana) and thence to the Okavango Swamp in Botswana. The tributaries of the Cubango River and several of the southern rivers flowing to the Atlantic are seasonal, completely dry much of the year.

Climate

Like the rest of tropical Africa, Angola experiences distinct, alternating rainy and dry seasons. In the north, the rainy season may last for as long as seven months--usually from September to April, with perhaps a brief slackening in January or February. In the south, the rainy season begins later, in November, and lasts until about February. The dry season (cacimbo) is often characterized by a heavy morning mist. In general, precipitation is higher in the north, but at any latitude it is greater in the interior than along the coast and increases with altitude.

Temperatures fall with distance from the equator and with altitude and tend to rise closer to the Atlantic Ocean. Thus at Soyo, at the mouth of the Congo River, the average annual temperature is about 26C, but it is under 16C at Huambo on the temperate central plateau. The coolest months are July and August (in the middle of the dry season), when frost may sometimes form at higher altitudes.

SOURCES: Library of Congress Country Studies/Area Handbook

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