Huang He floods, (1887, 1931, 1938), series of devastating floods in China caused by the overflowing of the Huang He (Yellow River), the country’s second longest river. These three floods collectively killed millions and are considered to be the three deadliest floods in history and among the most destructive natural disasters ever recorded.

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The Huang He, which has a length of 3,395 miles (5,464 km), is the main river of northern China, rising in the eastern Kunlun Mountains in Qinghai province in the west of the country and flowing generally east until it empties into the Bo Hai (Gulf of Chihli), an embayment of the Yellow Sea. The river takes its name from the large amounts of fine yellow sediment (loess) colouring its water. The extensive silt deposition in the river’s lower reaches across the North China Plain and the expansive stretches of flat land surrounding it have always made the area extremely prone to flooding. As the world’s most heavily silted river, the Huang He is estimated to have flooded some 1,500 times since the 2nd century bce, causing unimaginable death and devastation.

The most destructive of these floods occurred in August 1931, when 34,000 square miles (88,000 square km) of land were completely inundated, and approximately 8,000 square miles (21,000 square km) more were partially flooded, leaving 80 million people homeless. The estimates of the number of people killed by the flood (and the ensuing disease and famine) range from 850,000 to 4,000,000, making it by most estimates the deadliest natural disaster in recorded history. An earlier flood in September–October 1887 is thought to have killed 900,000 to 2,000,000 residents; a third, on June 9, 1938, was responsible for 500,000 to 900,000 deaths. The 1938 flood was caused by the destruction of the dikes near Kaifeng (Henan province) by Chinese Nationalist forces under Chiang Kai-shek in an effort to halt the advance of the invading Japanese troops during the Sino-Japanese War of 1937–45. The dikes were rebuilt in 1946–47, and the river was rediverted to its former course so that it again emptied into the Bo Hai.

Throughout most of its history, China has attempted to control the Huang He by building overflow channels and increasingly taller dikes, and in 1955 the Chinese embarked on an ambitious 50-year construction plan and flood-control program. This program included extensive dike construction, repair, and reinforcement, reforestation in the loess region, and the construction of a series of dams to control the river’s flow, produce electricity, and supply water for irrigation. Silt-retaining dams have not been completely effective (the accumulation of silt reduces the power-generating capacity of the dams), and they have been criticized by environmentalists. Continued silting in the Huang He has remained a serious problem; however, the river has not burst its banks since 1945, in large part because of the flood-control program.