Cyclone and Storm Surge - Iczmpwb.org

4.2
In US, there is a steady decrease in the death toll caused by tropical cyclones with an average death
toll of 7,000 during 1900-1910, 1,000 during 1950-1960 to only around 200 during 1990-1995
(Southern, 1991). This is attributed to effective warning system, good response from the affected
community and proper mitigation plan. In contrast, the property damage has been increased
considerably due to increasing activity in the coastal region and increase in material and labor cost.
However, in Southeast Asia and particularly in Indian region, there is no significant decrease in loss
of life, which is being reflected by the death toll of about 1,31,000 in 1991 Bangladesh cyclone and
about 10,000 in 1999 Orissa super cyclone. At the same time, the damage to properties has been
increased sharply in last few decades.
In the present study, the past datasets about the occurrence to tropical cyclones over this region (the
Bay of Bengal cyclones in the Indian region) is analyzed to determine the locations of high hazard
incidence.
4.2. Data Analysis
As mentioned above, the vulnerability of the West Bengal coastal districts / blocks are assessed by
analyzing the past cyclone datasets. For this purpose, the 114 years (1891-2004) past cyclone
datasets obtained from India Meteorological Department (tropical cyclone Atlas and other scientific
documents & journals) and Joint Typhoon Warning Centre (JTWC, USA), are used. The datasets
used to find out the number / percentage of storms / severe storms (developed over the Bay of
Bengal) crossed various countries bordering the Bay of Bengal and storms dissipated over the
ocean. Further, the frequency of storms/ severe storms crossing various state boundary of India is
calculated.
Figure-1 shows the number and percentage of cyclones crossing Indian coast-line and coast-line of
other countries viz., Bangladesh, Myanmar, Sri Lanka and those dissipated over the ocean itself.
This clearly shows that most of the cyclones developed over the Bay of Bengal crosses Indian coast
line (60.8%), the next highest being the number of cyclones dissipated over the sea. Thus in terms of
frequency, among the countries bordering Bay of Bengal, India is most vulnerable. It is must be
mentioned here that the vulnerability due tropical cyclones cannot be determined by solely by its
frequency of occurrence, the vulnerability depends on associated storm surge, coastal inundation /
flooding and socio-economy of the possible affected region.