Ivory Coast's government on Thursday called for the evacuation of all people living in flood-prone zones in Abidjan, the country's economic hub, after 18 were killed by flash floods triggered by torrential rain.After a national security council meeting headed by President Alassane Ouattara, the government announced "the destruction of structures on storm basins and drainage and sanitation work" and "the evacuation of all people living in risk zones."The statement, read on nationwide TV by Interior Minister Sidiki Diakite, did not say how many people would be affected by these measures or where they would be rehoused.Floods to 2.5 metres deep raced through some areas on Tuesday as Abidjan was hit by seven hours of exceptional rain.The affected areas ranged from the posh Cocody neighbourhood, where many embassies and the presidential palace are located, to the teeming working-class Yopougon neighbourhood.A coastal city of five million, Abidjan suffers from some severe infrastructure problems, including drainage and sewerage.Many homes are informal structures built in flood-prone areas, and deaths are common in the April to October rainy season. Twenty-eight people were killed on May 29, 1996. In addition to the 18 deaths in Abidjan, two other people died in flooding in the provinces.The authorities also said 1 650 troops would be deployed to help clear debris and unclog drains, and $3.4m would be earmarked to help victims.It also said that efforts would be stepped up to inform the public about flood risk, including weather alerts on the media and by mobile phone.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.