West Africa West Africa West Africa is the westernmost region of Africa. West Africa has been defined as including 17 countries: Benin, Burkina Faso, the island nation of Cape Verde, Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Mauritania, Niger, Nigeria, the islands of Saint Helena, Ascension and Tristan da Cunha, Senegal, Sierra Leone and Togo. The population of West Africa is estimated at about /1e6 round 0 million people as of . Studies of human mitochondrial DNA suggest that all humans share common ancestors from Africa, originated in the southwestern regions near the coastal border of Namibia and Angola at the
2009 West Africa floods Ouagadougou where rainfall in one day was equal to 25% of normal annual rainfall for the whole country. Countries in West Africa and the southern Sahel get most of their annual rainfall during the boreal summer months from June to September. This rainy season, also known as the West African monsoon, is associated with a seasonal reversal of prevailing winds in the lower atmosphere, where moist air is blown in from the Atlantic Ocean and released over the continent. The exceptionally heavy rainfall experienced in West Africa during the 2009 monsoon season is associated with the periodic warming of the