Cyclone in Bangladesh

Cyclones, very common, regular and annual phenomena affect Bangladesh frequently, specially the coastal area of Bangladesh. Disrupting the areas and causing extensive losses to people and property. Bangladesh with an area of 147,570 km² and 142319000 and 964 people live per km² (BBS, 2011) is the most vulnerable to several natural disasters. Each year natural calamities upset people’s lives in some part of the country. These extreme natural events are termed disasters when they adversely affect the whole environment, including human beings, their shelters, or the resources essential for their livelihoods.  The geographical setting of Bangladesh makes the country vulnerable to natural disasters, especially for cyclone. It is part of the humid tropics, with the Himalays on the north and the funnel-shaped coast touching the Bay of Bengal on the south. This peculiar geography of Bangladesh brings not only the life-giving Monsoons but also catastrophic cyclones, Norwester, tornadoes and floods. Among all the atmospheric disturbances, cyclones are the most destructive.

Cyclone a tropical storm or atmospheric turbulence involving circular motion of winds occurs in Bangladesh as a natural hazard. A tropical cyclone is a storm system characterized by a low pressure centre and numerous thunderstorms that produce strong winds and flooding rain. The Bay of Bengal is an ideal breeding ground for tropical cyclones. Cyclones are usually formed in the deep seas and hence their study has been very difficult. The diameter of a cyclone may range from 300 km to 600 km. A cyclone is accompanied by winds with speeds in excess of 118 km/hr, which flow toward the centre of a very strong low pressure. Pressure at the centre of the low may be 50-60 hPa (Hexa Pascal) less than in its outskirts. Cyclones are also accompanied by storm surges. Trends in Tropical Cyclones the Bay of Bengal is potentially energetic for cyclonic storms due to its favorable atmospheric and oceanic condition.

The cyclone which struck Bangladesh on the night of 29-30, April, 1991 was particularly severe causing widespread damage, killing 138,882 people and material damage was about USD 2.4 billion and human casualties numbered around 140,000. In 1970, a similar catastrophe claimed some 500,000 lives. Very recent, on 15 November 2007, Cylone Sidr struck the coastal region, the worst of its type since 1991, with winds of 250 km/h—155 miles per hour (mph)—and a five meter sea surge, killing more than 3,300 people.

Bangladesh Meteorological Department (BMD) is the source of cyclone warning in Bangladesh.BMD generates the warning and passes this on to public media and preparedness units for dissemination and follow-up action at periodic intervals. There are separate warning system for maritime ports and river ports.  The most dedicated agency for cyclone disaster information dissemination and mobilization at the coastal level is the Cyclone Preparedness Programme (CPP). The CPP is staffed by a small number of permanent officers at the headquarter in Dhaka and 8 coastal districts and comprises of little over 33000 volunteers, organized in teams of ten, which undertake specified cyclone emergency preparedness and post impact tasks. 

Reference:

Banglapedia, 1999.