The 1991 Bangladesh cyclone was a catastrophic tropical cyclone, being one of the deadliest tropical cyclones in recorded history, and one of the most powerful cyclones in the Indian Ocean. Forming out of a large area of convection over the Bay of Bengal on April 24, the tropical cyclone initially developed gradually while meandering over the southern Bay of Bengal. On April 28, the storm began to accelerate northeastwardly under the influence of the southwesterlies, and rapidly intensified to super cyclonic storm strength near the coast of Bangladesh on April 29. After making landfall in the Chittagong district of southeastern Bangladesh with winds of around , the cyclone rapidly weakened as it moved through northeastern India, degenerating into a remnant low over the Yunnan province in western China.

One of the most powerful tropical cyclones ever recorded in the basin, the tropical cyclone caused a 6.1 m (20 ft) storm surge, which inundated the coastline, causing at least 138,866 deaths and about US$1.7 billion (1991 USD) in damage. As a result of the catastrophic damage, the United States and other countries carried out Operation Sea Angel, one of the largest military relief efforts ever carried out.

Meteorological history

On April 22, 1991, a circulation formed in the southern Bay of Bengal from a persistent area of convection, or thunderstorms, near the equator in the eastern Indian Ocean. Within two days, the cloud mass encompassed most of the Bay of Bengal, focused on an area west of the Andaman and Nicobar Islands. On April 24, the India Meteorological Department (IMD) designated the system as a depression, and the Joint Typhoon Warning Center (JTWC) labeled the system as Tropical Cyclone 02B. Ships in the region reported winds of around around this time.

From its genesis, the storm moved northwestward, and early forecasts from the JTWC anticipated that trajectory would continue toward Andhra Pradesh in southeastern India, due to a westward-moving ridge over India. The cyclone gradually strengthened, amplified by a wind surge from the south. The IMD upgraded the depression to a cyclonic storm on April 25, and to a severe cyclonic storm on the following day. By April 26, wind shear had decreased to near zero as an anticyclone developed aloft the hurricane. Around this time, the cyclone rounded the western periphery of a large subtropical ridge over Thailand, and the storm turned northward between the ridge to the northeast and northwest. The IMD upgraded the system to a very severe cyclonic storm on April 27, estimating winds of 142 km/h (89 mph). By this time, the JTWC anticipated a future track toward the Ganges Delta region of eastern India and Bangladesh. Through its role as Regional Specialized Meteorological Center, the IMD issued warnings on the storm, designating it Super Cyclonic Storm BoB 1. The agency tracked the storm using satellite imagery, radar, and other meteorological stations. Time magazine referred to the storm as Cyclone Gorky.

The Bay of Bengal is prone to large storm surges, which is the rise in sea water accompanying a cyclone landfall. The low-lying coast of Bangladesh along the Bay of Bengal is heavily populated, The high velocity wind and the storm surge devastated the coastline. Although a concrete levee was in place near the mouth of the Karnaphuli River in Patenga, it was washed away by the storm surge. A large number of boats and smaller ships ran aground. The 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 to the ships. Most of the fighter planes belonging to the air force were damaged. The extensive damage caused the price of building materials to greatly increase. For an additional three to four weeks after the storm had dissipated, mass land erosion resulted in more and more farmers losing their land, and therefore, the number of unemployed rose. In several areas, up to 90 percent of crops had been washed away. The shrimp farms and salt industry were left devastated.

Elsewhere

The JTWC tracked the cyclone as moving northeastward from Bangladesh into northern Myanmar, dissipating in western China over Yunnan province. The government implemented a reforestation program to mitigate future flooding issues.

A survey concluded that the cyclone mostly killed children of under 10 years of age and women above 40 years.

Operation Sea Angel

thumb|Bangladeshis unloading international aid from a US helicopter

The United States amphibious task-force, consisting of 15 ships and 2,500 men, returning to the US after the Gulf War was diverted to the Bay of Bengal to provide relief to an estimated 1.7 million survivors. 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 to provide humanitarian assistance. A Contingency Joint Task Force under the command of Lieutenant General Henry C. Stackpole, consisting of over 400 Marines and 3,000 sailors, was subsequently sent to Bangladesh to provide food, water, and medical care to nearly two million people. The efforts of U.S. troops, which included 3,300 tons of supplies, are credited with having saved as many as 200,000 lives. The relief was delivered to the hard-hit coastal areas and low-lying islands in the Bay of Bengal by helicopter, boat and amphibious craft.

The US military also provided medical and engineering teams to work with their Bangladeshi counterparts

After the departure of the task force, 500 military personnel, two C-130 cargo planes, five Blackhawk helicopters and four small landing craft from the task force remained to help finish off relief operations in outlying districts and rebuild warehouses. The amphibious landing ship (LKA-116) delivered large quantities of intravenous solution from Japan to aid in the treatment of cyclone survivors.

See also

  • 1970 Bhola cyclone – The deadliest tropical cyclone recorded worldwide, affecting similar areas
  • 1988 Bangladesh cyclone – Another powerful cyclone that followed a similar path
  • 1994 Bangladesh cyclone – Another powerful cyclone that followed a similar path
  • Cyclone Amphan – Took a similar path and had a similar intensity
  • Cyclone Sidr
  • Cyclone Nargis
  • Cyclone Mora
  • List of Bangladesh tropical cyclones
  • List of disasters in Bangladesh by death toll
  • List of rivers of Bangladesh
  • List of natural disasters by death toll
  • 1991 BTC Club Cup

Notes

References

  • from NIRAPAD disaster response organisation.
  • Indian Cyclone Fact Sheet
  • JTWC report