Tropical cyclones are depressions originating over Bay of Bengal. These tropical cyclones are often destructive. They cause heavy rains. These cyclones strike West Bengal and Bangladesh (Ganga Delta). They cross theEastern coast and affect the states of Orissa, Andhra Pradesh, Tamil Nadu and Kerala. The thickly populated deltas of Mahanadi, Godavari, Krishna and Kaveri are the main targets of these tropical cyclones.