Analyzing the Compound Hazards Associated with The Landfalling Cyclones Over the Indian Subcontinent

Abstract

Tropical cyclones (TCs) rank among the most destructive natural disasters, causing significant mortalities, fatalities, widespread infrastructure damage, and ecological harm each year. The Indian landmass, bounded by the Bay of Bengal (BOB) and the Arabian Sea (AS) sub-basins, is highly prone to the impacts of cyclones, and the densely populated coastal regions further magnify the degree of risks. This research examines the variability in individual and compound hazards owing to torrential rainfall and severe winds associated with landfalling cyclones, estimates the probable long-term risks, and investigates the influence of underlying driving factors on the variability and magnitude of the hazards. The results show an increase in the frequency of AS cyclones, whereas a near-stable trend in BOB cyclones has been observed in the recent era. The extreme rainfall hazards are most pronounced across the north-eastern coastal states and their inland regions. Whereas, the wind hazards are more prominent along the north-eastern coastline areas, followed by significant impacts along the western and south-eastern coasts. The compound hazards concerning the co-occurrence of rainfall and severe winds, show a greater risk to West Bengal and northern Andhra Pradesh in the east, and Gujarat in the west. In the near term (< 10 years), extreme rainfall events are projected to be most frequent over Odisha and adjoining coastal regions, as well as in Gujarat and Madhya Pradesh, whereas wind-related hazards are expected to impact predominantly the eastern and north-western coasts. Besides, the maximum destructive potential from compound hazards is anticipated along the northern segment of the eastern coast within 50 years, with moderate hazard exposure projected for the north-eastern coastal states and adjacent areas within 20 years. The variability in the tropical cyclone landfall characteristics and their associated hazard is largely governed by the changes in the driving factors.