1991 Bangladesh cyclone Super Cyclonic Storm BOB 01 Super cyclonic storm (IMD) Category 5 tropical cyclone (SSHS) Visible satellite image from 06:23 UTC on April 29, 1991. The cyclone was a Category 4 cyclone, and was rapidly intensifying, when this image was taken. Formed April 24, 1991 Dissipated April 30, 1991 3-minute sustained: Highest 240 km/h (150 mph) winds 1-minute sustained: 260 km/h (160 mph) Lowest pressure 918 mbar (hPa; 27.11 inHg) Fatalities 138,866 total Damage $1.7 billion (1991 USD) Areas Bangladesh affected Part of the 1991 North Indian Ocean cyclone seasonThe 1991 Bangladesh cyclone (IMD designation:BOB 01, JTWC designation:02B) was amongthe deadliest tropical cyclones on record. On the night of 29 April 1991 a powerful tropicalcyclone struck the Chittagong district of southeastern Bangladesh with winds of around250 km/h (155 mph). The storm forced a 6 metre (20 ft) storm surge inland over a wide area,killing at least 138,000 people and leaving as many as 10 million homeless.
 Meteorological historyStorm pathAn area of persistent cloudiness, in part due to the monsoon trough, developed into a tropicaldepression on April 22 in the Bay of Bengal. The wind speed and overall size increased, with thedepression becoming Tropical Storm 02B on the 24th. The enormous wind field at the timeencompassed nearly the entire bay.The tropical storm continued slowly northwestward, slowly strengthening to a cyclone-strengthstorm on the 27th. The cyclone moved between a high pressure system to its northwest and east,and as mid-level westerlies met up with the storm, the cyclone moved northeastward. Thewesterlies enhanced upper level outflow, and in combination with warm water temperatures thecyclone steadily strengthened to a major hurricane on the 28th.On the 28th and 29th, as the system increased its speed to the north-northeast, the cyclonerapidly intensified to a 160 mph Cyclone, the equivalent to a Category 5 hurricane. Late on the29th, Cyclone 02B made landfall a short distance south of Chittagong as a slightly weaker155 mph Category 4 Cyclone. The storm rapidly weakened over land, and dissipated on the 30thover southeast Asia. Impact FatalitiesFlooding around a river in BangladeshAt least 138,000 people were killed by the storm, with the majority of deaths in the Chittagongarea. Most deaths were from drowning, with the highest mortality among children and theelderly. Although cyclone shelters had been built after the 1970 Bhola cyclone, many had just afew hours of warning and did not know where to go for shelter. Others who knew about thestorm refused to evacuate because they did not believe the storm would be as bad as forecast.Even so it is estimated over 2 million people did evacuate from the most dangerous areas,possibly mitigating the disaster substantially. Property damageA damaged village in Bangladesh, surrounded by flooded fields, three weeks after the storm hadstruck
The storm caused an estimated $1.5 billion (1991 US dollars) in damage. The high velocity windand the storm surge devastated the coastline. Although a concrete levee was in place near themouth of the Karnaphuli River in Patenga, it was washed away by the storm surge. The cycloneuprooted a 100-ton crane from the Port of Chittagong, and smashed it on the Karnaphuli RiverBridge, effectively breaking it into two partitions. A large number of boats and smaller ships ranaground. Bangladesh Navy and Bangladesh Air Force, both of which had bases in Chittagong,were also heavily hit. The Isha Khan Naval Base at Patenga was flooded, with heavy damages tothe ships. Most of the fighter planes belonging to the air force were damaged. Approximately1 million homes were destroyed, leaving about 10 million people (a substantial portion ofBangladeshs population) homeless. Environmental impactThe storm surge subsequently caused the embankment, as well as whole villages, to be sweptaway. For an additional three to four weeks after the storm had dissipated, mass land erosionresulted in more and more farmers losing their land, and therefore, the number of unemployedrose. International responseBangladeshis unloading international aid from a US helicopterThe United States amphibious task-force, consisting of 15 ships and 2,500 men, returning to theUS after the Gulf War was diverted to the Bay of Bengal. This was part of Operation Sea Angel,one of the largest military disaster relief efforts ever carried out, with the United Kingdom,China, India, Pakistan and Japan also participating.Operation Sea Angel began on May 10, 1991 when President Bush directed the US military toprovide humanitarian assistance. A Contingency Joint Task Force under the command ofLieutenant General Henry C. Stackpole, consisting of over 7,000 US soldiers, was subsequentlysent to Bangladesh to provide food, water, and medical care to nearly two million people. Theefforts of U.S. troops, which included 3,000 tons of supplies, are credited with having saved asmany as 200,000 lives.