1970 Bhola Cyclone: The Deadliest Tropical Cyclone on Record

The 1970 Bhola cyclone struck the coast of East Pakistan, now Bangladesh, on the night of 12–13 November 1970. Its storm surge swept over low islands and coastal plains in the Ganges–Brahmaputra delta, killing an estimated 300,000 to 500,000 people. It is regarded as the deadliest tropical cyclone ever recorded, and the government’s response helped set off the crisis that led to Bangladesh’s independence.

Background: a vulnerable delta

The Bay of Bengal is one of the world’s most dangerous places for cyclones. Its funnel shape and shallow coastal waters can pile seawater into towering surges when storms approach from the south.

The coast of East Pakistan lies at the mouth of the Ganges, Brahmaputra and Meghna rivers. Much of it is barely above sea level, with many low islands and new silt banks, called chars, where poor farmers and fishermen settled. Islands such as Bhola, Hatiya and Manpura were densely populated, and in November many seasonal labourers had arrived to harvest the rice crop.

East Pakistan was then the eastern wing of Pakistan, separated from West Pakistan by about 1,600 kilometres of India. Political and economic power lay mostly in the west, and many Bengalis felt neglected by the central government under President Yahya Khan.

The storm

The cyclone formed over the central Bay of Bengal around 8 November 1970 and moved north, strengthening as it went. American weather satellites tracked it, and Pakistani meteorologists issued warnings, but the warning system did not clearly tell coastal people how dangerous the threat was or where to go.

The storm reached its peak shortly before landfall, with maximum sustained winds of about 185 km/h (115 mph), comparable to a Category 3 hurricane. It came ashore on the evening of 12 November and through the night, coinciding with high tide.

The storm surge was catastrophic. Reports put its height at up to about 10 metres (33 feet) in places. Water swept across islands and coastal districts with little warning, destroying houses made of mud, bamboo and thatch and carrying people, livestock and crops out to sea.

The scale of the disaster

The exact death toll will never be known. Estimates usually range from 300,000 to 500,000. In some areas, almost entire communities vanished. Tazumuddin, an administrative area on Bhola Island, reportedly lost close to half its population.

Survivors faced shortages of food, clean water and shelter. Rice crops were ruined, and huge numbers of cattle drowned. Fishing boats were destroyed along the coast, and many fishermen at sea were lost. Officials and journalists who reached the islands days later found bodies in fields and rivers.

The government response

The response from the central government was widely criticised as slow and inadequate. President Yahya Khan was returning from a state visit to China when the storm struck, and he visited the affected area only briefly. Relief supplies were slow to reach the islands because of a shortage of helicopters, boats and organisation.

International aid came from many countries, including the United States, Britain and India, and from charities such as the Red Cross. Helicopters and boats from abroad delivered food and medicine. Yet many Bengalis felt that the response showed how little the authorities in West Pakistan cared about the east.

Political leaders in East Pakistan seized on this anger. Maulana Abdul Hamid Khan Bhashani, a veteran left-wing leader, publicly attacked the government. Sheikh Mujibur Rahman, leader of the Awami League, argued that the disaster proved East Pakistan needed control over its own affairs.

Political consequences

Pakistan’s first general election based on universal adult franchise was held on 7 December 1970, less than four weeks after the cyclone. Voting in several of the worst-hit constituencies was postponed until January 1971.

The Awami League won 160 of the 162 general seats allocated to East Pakistan, giving it an overall majority in the National Assembly. Leaders in West Pakistan, including the military government and Zulfikar Ali Bhutto’s Pakistan Peoples Party, were unwilling to hand power to Mujib on his terms.

Talks broke down, and on 25 March 1971 the army launched a crackdown in East Pakistan. This led to the Bangladesh Liberation War, in which India intervened in December 1971, and to the creation of independent Bangladesh. The cyclone did not cause the war on its own, but historians see it as a major step in turning Bengali resentment into a demand for independence.

Legacy: learning to prepare

Independent Bangladesh made cyclone preparedness a priority. In 1972 the government and the Bangladesh Red Crescent Society created the Cyclone Preparedness Programme, which trains tens of thousands of volunteers to spread warnings using radios, megaphones and flags.

The country also built thousands of raised concrete cyclone shelters and coastal embankments. These efforts have saved many lives. A severe cyclone in 1991 still killed around 138,000 people, but later storms such as Cyclone Sidr in 2007 caused far fewer deaths, in the low thousands, despite similar strength.

In 2017 the World Meteorological Organization formally recognised the Bhola cyclone as the deadliest tropical cyclone on record. Its toll far exceeds that of other notorious storms in the region, such as Cyclone Nargis in Myanmar.

Why the storm surge was so deadly

Several factors combined to make the Bhola cyclone so lethal. The coast of the Bay of Bengal slopes very gently, so the sea can pile up into a high surge as a storm approaches. The cyclone also arrived close to high tide, adding to the height of the water.

The islands and chars were flat, with few trees, hills or strong buildings for people to climb. Most homes were built of mud, bamboo and thatch and were simply washed away. There were very few purpose-built cyclone shelters.

Warnings were another weakness. Radio broadcasts used technical terms that many listeners did not understand, and many poor families did not own radios. Even people who heard the warnings often had nowhere safe to go, and some were reluctant to leave their homes, animals and crops.

Finally, the storm hit at night. In the darkness, people could not see the water coming, and many were swept away while asleep or trying to escape. Survivors often clung to trees or floating debris until morning.

By the numbers

Timeline

• 1970, 8 November: A depression forms over the central Bay of Bengal.
• 1970, 11 November: The storm intensifies into a severe cyclone heading north.
• 1970, 12–13 November: Landfall on the East Pakistan coast at night; storm surge floods islands and coast.
• 1970, mid-November: International relief operations begin amid criticism of the government’s response.
• 1970, 7 December: General election held; the Awami League wins almost all East Pakistan seats.
• 1971, 17 January: Delayed voting held in cyclone-affected constituencies.
• 1971, 25 March: Pakistani army crackdown begins in East Pakistan.
• 1971, 16 December: Pakistani forces surrender in Dhaka; Bangladesh becomes independent.
• 1972: Bangladesh launches the Cyclone Preparedness Programme.

Why it matters

The Bhola cyclone was one of the worst natural disasters of the twentieth century. It exposed how poverty, geography and weak government could combine to multiply deaths, and it played a part in the birth of a nation. Bangladesh’s later success in cutting cyclone deaths is one of the clearest examples of how preparation can save lives.