The heavy rainfall and floods over the northeastern interior of South Africa during February 2000 : research article

Exceptionally heavy rains fell over the northeastern parts of South Africa, Mozambique and Zimbabwe during February 2000. Disastrous flooding resulted, hundreds of lives were lost and the damage to the infrastructure of the region severely hampered economic and agricultural development. Most of the rainfall occurred during the periods 5-10 February and 22-25 February and in both instances were caused by tropical weather systems that moved from east to west over the subcontinent. The two tropical weather systems had anomalously long life times overland. A brief overview of the rainfall affecting South Africa is provided. Monthly rainfall totals exceeded 1000 mm along the eastern escarpment of the Northern Province, with 24-hour rainfall greater than 400 mm on 6 and 24 February. A nearly perpendicular flow of moist air over the eastern escarpment of South Africa was responsible for the exceptionally heavy rainfall over these areas. The rainfall forecast of the South AfricanWeather Bureau Eta model shows encouraging results as far the geographical distribution of rainfall is concerned but the rainfall totals were underestimated by some 50%. A thorough investigation into the dynamic processes involved in maintaining the tropical nature of the weather systems overland is recommended.