The flooding is a result of slow-moving storm Issa, which has dumped several months' worth of rain over Durban and surrounding cities since Monday. As much as 450 mm (nearly 18 inches) has been recorded along the coast of KwaZulu-Natal in that time. In Durban, 307 mm (nearly 12 inches) fell in only 24 hours, which is more than four times the normal amount for the entire month of April.