''Efundja'', the annual seasonal flooding of the northern parts of the country, often causes not only damage to infrastructure but loss of life. The rains that cause these floods originate in Angola, flow into Namibia's Cuvelai-Etosha Basin, and fill the ''oshanas'' (Oshiwambo: flood plains) there. The worst floods  occurred in March 2011 and displaced 21,000 people.