Tropical cyclone vulnerability assessment for India

Tropical cyclones affect millions of lives in the Indian subcontinent which makes the region highly vulnerable to cyclones. Classifying the region’s vulnerability greatly helps the stakeholders involved in the disaster management associated with tropical cyclones. This study is a comprehensive assessment of India’s vulnerability to cyclones of different categories prepared at district level. It is based on recently updated cyclone track data, and considers both meteorological parameters such as surface-level winds, daily rainfall, storm surge height and socioeconomic parameters like population and household densities. Statistical tools like the cyclone return period as well as the landfall frequency count are also calculated for cyclones of varied intensities. A normalized cyclone vulnerability index is defined as a combination of above parameters that provides an overall vulnerability of each district to cyclonic, severe cyclonic and the total cyclonic storm categories. Results show that coastal districts of the northern most states of the east coast consisting of West Bengal and Odisha are most vulnerable to tropical cyclones followed by districts of Andhra Pradesh and Tamil Nadu on longer timescale. However, a southward shift in the cyclone activity as well as vulnerability is observed for the recent period. Along the West Coast, coastal districts of Gujarat show an increased vulnerability in the recent times than before. In terms of percentage of districts extremely vulnerable to cyclones, Andhra Pradesh dominates the list with 40–50% followed by Odisha (29–34%), West Bengal (13–14%) and Tamil Nadu (7–13%).