The Bay of Bengal is a known breeding ground of tropical cyclone and hit the coastal area of Bangladesh during pre-monsoon (April and May) and post-monsoon (October and November). One of the reasons why it hits Bangladesh coast often is the conical shape of the Bay of Bengal. Over the last 50 years, 15 severe cyclones with wind speed ranging from 140 to 225 km/hr have hit the coastal area of Bangladesh of which 7 hit in pre-monsoon and rest in the post-monsoon season.
Tropical cyclones are the most talked climatic events in the subcontinent especially in Bangladesh and India. The coastal area of Bangladesh is more vulnerable to cyclones in the Bay of Bengal regions. Historical record of cyclones formed in Bay of Bengal revealed that 15 most damaging cyclones have struck Bangladesh very badly. Among those, 4 were catastrophic and killer cyclones which struck in 1919, 1970, 1991 and 2007. The damaging cyclonic events have been identified depending on wind speed and surge height. The cyclones which have wind speed of 120 kph and surge height of 4.5 m have been taken into account.