Bhola Cyclone

The Bhola Cyclone, which struck the Bay of Bengal coast in November 1970, is generally regarded as the deadliest tropical cyclone ever recorded. It devastated the low-lying delta of what was then East Pakistan, now Bangladesh, and killed an estimated 300,000 to 500,000 people. The exact toll will never be known, and the storm mattered far beyond its human cost: the government's response became a catalyst for the political crisis that led to the creation of Bangladesh.

The region's geography made catastrophe almost inevitable. The Ganges-Brahmaputra delta is a maze of river channels and flat islands, many barely above sea level, home to some of the densest rural populations on Earth. Farmers and fishing communities lived on newly formed silt islands, or chars, with little high ground or solid shelter. The funnel shape of the northern Bay of Bengal also concentrates storm surges, and the area had suffered deadly cyclones before. Communications were poor, and warnings often failed to reach remote villages or were not taken seriously.

The storm formed over the central Bay of Bengal in the second week of November and moved north, reaching the coast on the night of 12 to 13 November, at about the time of a high tide. Its winds were comparable to a strong hurricane, but the main killer was the storm surge, which swept across the islands and coastal districts, some of it reportedly many meters high. Bhola Island and the Tazumuddin area were among the hardest hit. Entire villages were washed away, along with crops, livestock and fishing fleets. Many victims drowned in the dark, and the survivors faced hunger, contaminated water and disease.

The relief effort quickly became controversial. Many people in East Pakistan felt the central government, based in West Pakistan, was slow and indifferent, and the response was widely criticized at home and abroad. Foreign governments and aid organizations, including the Pakistani military and international donors, sent assistance, but resentment grew. Historians debate how much the cyclone alone changed events, since East Pakistani grievances over political representation and economic inequality were already deep.

Those tensions surfaced in the general election held in December 1970, in which the Awami League, led by Sheikh Mujibur Rahman, won an overwhelming majority of seats. The central authorities refused to hand over power, and the dispute escalated into civil conflict and the Bangladesh Liberation War of 1971, ending with independence. The cyclone also spurred later investment in forecasting, early warning systems and storm shelters in Bangladesh, which have helped reduce deaths in later storms.