Bangladesh Cyclone – October 31, 1876

A cyclone in the area we now know as Bangladesh destroyed the city of Chittagong. At least 200,000 people in Chittagong and its surrounding area died as a result of the cyclone.

On October 31, 1876, the community of Chittagong, in a part of India that is now in the nation of Bangladesh, experienced a powerful cyclone that swept inland up the River Meghna, part of the Ganges River’s delta. As the surge of water moved upstream into the shallower and narrower stretches of the river it rose in height until it became a monstrous wall of ocean water, thirty to forty feet high. Bangladesh, on the eastern part of the Bay of Bengal, experiences cyclones twice a year, in October and in May. These two months represent the turning points of the monsoon winds. In May they begin to move on shore and in October they move southward from the cold air mass in the north to dominate the atmosphere of India for almost six months. It seems that these turning points, because they represent for a time a mixing of the two contrasting wind systems, trigger the cyclones. The impact of this cyclone in 1876 was devastating in every way. A hundred thousand persons drowned and another hundred thousand perished from diseases or famine.

There is, initially, an accumulation of water in the various small sea inlets along the coast as the cyclone pushes water toward the land. This is a slow process because the Bay of Bengal is quite shallow for a distance of several miles outward from the land. Other factors too, in addition to the depth of the ocean, determine the rate at which water accumulates. A spring tide, a higher than normal level of tidal water, if it were to coincide with the arrival of a cyclone, would greatly increase the breadth of destruction because tidal waters influence the entire shore. This coincidence occurred several times in the recent past, in 1970, 1981, and 1991, fortunately with less loss of life, presumably because disaster preparedness was greater than in 1876. The wind strength of the cyclone and the angle of impact with the shore are two other factors influencing the amount of destruction.

Bangladesh seems to have received more of the types of cyclones that result in high death rates than has any other country in South or Southeast Asia. One statement that gives support to this claim is based on a list of deaths from cyclones that occurred only in those countries and in those cyclones in which there were more than 5,000 deaths. The data reveals that Bangladesh featured in more than half of the countries listed. One physical factor in the environment of Bangladesh may be a contributing cause. The country’s overall low elevation makes it easy for relatively small storms to transform its coastal area into a vast sea. With regard to the future, scientists have debated the implications of global warming with respect to the nature of cyclones in the Bay of Bengal. The only tentative conclusions arrived at to date are that sea temperatures will increase and these cyclones, as a result, will likely be more intense and therefore more destructive.