Cyclone Sidr – A History
By George Pararas-Carayannis
Cyclone Sidr was one of the 10 strongest cyclones to hit Bangladesh between 1876 and 2007. SIDR developed in the Bay of Bengal in early November 2007. It further intensified into a category 4 storm system (on the Saffir-Simpson Scale) with peak sustained winds of up to 215 km/hour, peaking at 260 km/h. The cyclone made landfall in Bangladesh in the evening of November 15. SIDR and its surge resulted in thousands of deaths and massive destruction of coastal communities.
Formation and Path of Sidr
November 9 - An air mass disturbance with weak low-level circulation began developing in the central Bay of Bengal, southeast of the Andaman Islands, in close proximity to the Nicobar Islands.
Moderate upper-level wind shear inhibited its organised development, however strong diffluence aided in developing convection.
November 11- The anomalous weather system was still somewhat south of the Andaman Islands. A better defined cyclonic circulation developed when the vertical shear began decreasing. Based on that, a tropical cyclone formation alert was issued for the region. Later that day, when winds reached 65 km/h, the India Meteorological Department (IMD) designated the system as a tropical depression. The system intensified as it moved slowly in a north-westward direction. The Joint Typhoon Warning Centre (JTWC) upgraded it to the designation of tropical cyclone.
November 12 - As the system further intensified, IMD further upgraded the weather system to a severe cyclonic storm and named it Sidr (hole or eye in Sinhalese language).
November 15 - By morning, Cyclone Sidr had moved considerably northward towards Indias eastern border with Bangladesh. It had strengthened to reach Category-4 tropical cyclone status, with peak sustained winds of 215 km/h. According to JTWC best track, Cyclone Sidr subsequently reached peak wind velocities of up to 260 km/h. Later that day, it appeared that the brunt of the cyclones force would be felt by the less populated areas of the Sundarban mangrove forests, which stretch along the western coast of Bangladesh. However, that did not happen. Around 1700 GMT (11PM BST) that day, with sustained winds of 215 km/h, Sidr made direct landfall in the district of Bagerhat, a highly-populated area of the country. A catastrophic storm surge flooded the area and caused most of the deaths and damage.
November 16 Cyclone Sidr weakened considerably as it moved over land.
Cyclone Surge
Bangladesh is a country that is almost entirely situated on an enormous delta that was formed by the confluence of the Ganges, Brahmaputra and Meghna rivers and their tributaries. This extensive river system is constantly fed by waters of melting snow from the Himalayas. Thus, the entire country is mostly flat and extremely vulnerable to flooding. Cyclone Sidr generated maximum flooding. The districts of Patuakhali, Barguna and Jhalokathi were hit hard by the storm surge that was over five metres (16 ft) in height. Fortunately, the cyclone made landfall when the tide was low, so the surge was not as high as it could have been.
Death Toll and Damages
Most of the cyclones that have made landfall in Bangladesh in the past have caused thousands of deaths. Sidr was no exception. According to official accounts 3,447 people lost their lives. However, the actual death toll may never be known with certainty. It is estimated that perhaps up to 10,000 people may have lost their lives, with thousands more injured, or missing. Thousands more were displaced and became homeless.
The damage in Bangladesh was extensive. About a quarter of the Sunderbans, a World Heritage site that is home to the rare Royal Bengal Tigers, was damaged. The districts of Patuakhali, Barguna and Jhalokati were hit hard by the cyclones surge of over five meters. There was extensive flood damage in Barisal and Mongla port as the cyclones surge rolled in. In Mathbaria, one of the towns in the very centre of the devastation, there was hardly anything left standing, except for a few brick and concrete buildings. Houses and schools were demolished. The storms surge washed away all roads in the region. About 500 fishing boats were unaccounted for and over 3,000 fishermen were reported missing.
Much of the capital of Dhaka was also severely affected due to the winds and the flooding which affected the citys infrastructure. Electricity and water services, as well as internet and mobile networks were disrupted.
The agricultural industry was devastated by the flooding which covered about 1 million hectares of farmable land. In brief, Sidr affected about 2 million families, comprising about 9 million people. More than 1.5 million homes were destroyed.
Advance Warning
There was advance knowledge that cyclone SIDR would make landfall in Bangladesh. The warning was disseminated by emergency response authorities, prompting massive evacuations of the low-lying coastal areas. A total of 2 million people were evacuated to emergency shelters and that probably contributed to the lower death toll. However, in spite of the warning, thousands of people were stranded on tiny islands dotting the coastline, with no place to go because of the flatness of the land and low elevation above sea level. There was simply no higher ground or shelters on stilts to evacuate to. Overall, the early warning system, preparedness and massive evacuations, resulted in a much lower death toll than the catastrophic 1991 cyclone, which hit southeast Chittagong region on April 29 and killed more than 140,000 people and left as many as 10 million others homeless.
Past Cyclones
Bangladesh is extremely vulnerable to seasonal cyclones and floods. This is because a very large part of Bangladesh is located on river deltas with low elevation above the sea. These areas routinely suffer large-scale losses of life and property. Cyclones and depressions threaten the country every year during pre-monsoon and post monsoon seasons. In the past, cyclones and their surges originating in the Bay of Bengal, have killed hundreds of thousands of people.
In 1960, a cyclone with winds up to 210 km/h made land fall in Bangladesh and killed about 10,000 people. Another cyclone in 1961, with winds of up to 161 km/h killed 12,500 people. The 1963 cyclone that made landfall in coastal Chittagong region killed more than 11,500 people and destroyed about 1 million homes.
The deadliest of all was the cyclone of November 12, 1970. It made landfall with winds of up to 222 km/h and a surge that was 10 metres high. It created havoc in the coastal districts of Barisal, Patuakhali, Noakhali and Bhola. It destroyed Chittagong and many coastal villages, killing about half a million people.
Another cyclone in 1985 ripped through Urir Char and devastated Chittagong, Coxs Bazar and coastal islands with 154 km/h winds and 4.5 metre high surge that killed about 11,000 people. More recently, a cyclone on April 29, 1991 with 225 km/h winds swept over the coastal areas of Chittagong with 8-metre (25 ft) high tidal surge and killed an estimated 143,000 people. n
Source: www.drgeorgepc.com
