Tropical cyclone hazards and warning and disaster mitigation systems in India

Abstract

The main features of a cyclone that cause death and destruction are: (1) Storm surge, a rapid increase in sea level along the coast, primarily caused by the strong surface wind field of the cyclone as it approaches the coast, (2) the violent sustained wind and wind gusts and cyclone-spawned tornadoes, and (3) the heavy rain and consequent flooding. The paper describes the structure of a tropical cyclone of hurricane intensity and its damage potential, cyclone detection, tracking, forecasting and warning systems. It concludes that with over a hundred years of research and operational experience on cyclones available with the meteorological community and with theinsat and cyclone detection radar network, India has now an efficient cyclone warning system. This system would however benefit from further sophistication notably the use of Doppler Radars for cyclone wind field monitoring and an aircraft reconnaissance facility for probing cyclones. Research is needed to develop techniques for better forecasting of the tracks of cyclones more than a day ahead and also their intensity changes. Cyclone disaster mitigation arrangements were organised in the maritime states of India only during the last 25 years. This relatively young field requires more developmental work, particularly in coastal area planning to reduce property losses, and exploration of alternative approaches to large-scale evacuation of the coastal population threatened by cyclones to distant temporary shelters.