Probabilistic assessment of tropical cyclones’ extreme wind speed in the Bay of Bengal: implications for future cyclonic hazard

Tropical cyclones (TCs) of the Bay of Bengal (BoB) cause catastrophic loss over the coasts at the time of landfall in India, Bangladesh, Myanmar and Sri Lanka. To strengthen TCs’ disaster risk management works, it is obligatory to estimate their return periods and probability of occurrence. Therefore, in this study, extreme value theory has been employed for probabilistic assessment of BoB TCs’ extreme wind speed. For TCs’ extreme wind speed, Joint Typhoon Warning Centre data have been used for 44 years (1972–2015). The analyses exhibit that the cumulative probability of exceedance decreases from the cyclonic storms (CSs) to greater than supercyclonic storms (SupCSs) intensity. The exceedance probability of occurrence of CSs is about 99%, while it is about 15% for SupCSs and of greater intensity in the BoB. The most probable annual maxima show that at least one TC of hurricane category I (wind speed ≥ 64 knots) can occur every year. The return period exhibits that on an average one CS can occur once in about 0.27-years, whereas one SupCS can occur once in about 6 years in the BoB. Spatial plots of return period and probability with respect to TCs’ extreme wind speed exhibit that coasts of West Bengal, Orissa, Andhra Pradesh and Tamil Nadu in India and entire Bangladesh and adjacent Myanmar coast are at high risk. This study provides a unique insight into BoB coastal countries TCs’ extreme wind risk. It is assumed that estimated TCs’ wind speed will be useful for government officials, scientists, disaster managers, engineers, public interest groups and private sectors.