Investigation of the Ferry Disaster Incident of Assam (India) on April 30, 2012
Kalyan Kumar Das
Department of Mechanical Engineering, Assam Engineering College, Guwahati-781013, India
This paper deals with a ferry disaster that occurred in the state of Assam due to a severe thunderstorm. Such storms are locally called Kalbaishakhi or “Nor’westers.” Kalbaishakhi storms are due to pre monsoon (March to May) mesoscale convective systems that develop over the Gangetic West Bengal and the north-eastern part of India. Severe thunderstorms are responsible globally for large amount of wind induced damage. Unlike large or continental cyclones, severe local storms intensify very rapidly and dissipate after causing damage. The worst type of severe local storm is the tornado, which is characterized by a fast rotating column of rising air that originates on or near the ground, where the air swirls and converges at high speed. Another type is the downburst, an antitornadic storm characterized by slow rotating column of descending air, that bursts out violently upon reaching the ground. The focus of this paper is a large scale destroyer of life believed to have occurred due to a downburst from a severe thunderstorm. Such unfortunate natural calamities are eye-openers to agencies working on disaster mitigation and are an important reason for them to implement measures safeguarding against loss of life and destruction of property.
-  T. T. Fujita, “Tornadoes and downbursts in the context of generalized planetary scales,” J. Atmos. Sci., Vol.38, pp. 1511-1534, 1981.
-  T. T. Fujita, “Downburst: Microburst and Macroburst,” Univ. of Chicago Press, Chicago, Illinois, 1985.