Cyclone Induced Storm Surge

Tropical cyclones are among the most devastating extreme natural events. When a cyclone approaches a coast, it can induce an increase of sea level, called storm surge. This storm surge can cause severe flooding of vast coastal low-lying areas and leads to profound societal and economic impacts. This is especially the case for the regions surrounded by the semi-enclosed sea of the Bay of Bengal. by_Bernard et. al., 2022

Figure:The charts provide overview of the most frequent natural disaster in Bangladesh and understand the impacts of those disasters on human populations

The storm surges that accompany cyclones cause more destruction than strong winds associated with cyclones. These cyclone-induced storm surges are more frequent during the pre-monsoon (May) and post-monsoon (October–November) season, when the flow of the Ganges–Brahmaputra river system is relatively low and the rainfall is moderate, thereby reducing the likelihood of experiencing compound events, i.e., combined with other flood types such as pluvial and fluvial.

Figure-2: Cyclonic inundation level with a 50-year return period estimated from a large number of hydrodynamic simulations (Khan et al., 2019). This means that at a particular location, the reported flooding height, due to cyclonic surges, is expected to be observed once in 50 years (Bernard et. al., 2022)

Figure-3: Population density in coastal districts of Bangladesh. SCHISM: Semi-implicit Cross-scale Hydroscience Integrated System Model (Bernard et. al., 2022).

Figure-4: Bangladesh Cyclone Prone Areas