Red River Delta Flood of 1971

A severe flood of the Red River in North Vietnam kills an estimated 100,000 people on this day in 1971.

This remarkable flood was one of the century’s most serious weather events, but because the Vietnam War was going on at the time, relatively few details about the disaster are available.

What is known is that the Red River, which runs near the capital city of Hanoi, experienced a "250-year" flood. Torrential rains simply overwhelmed the dyke system around the heavily populated delta area, which is not far above sea level. As well as directly killing thousands of people, the flood also wiped out valuable crops, causing further hardship, especially as it occurred during wartime.

Though many more reservoirs have since been built in the Hanoi region, the area remains vulnerable to flooding.

Within a period of 45 years (1900-1945), there were 18 years in which dykes failed, or one dyke failure with crop losses every two to three years on average. In the 1945 flood, the dyke system failed in 79 places, flooding 11. Provinces over a cultivated area of 312,000 ha and affecting about 4 million people. The 1971 flood caused the dykes to fail in 3 large sections, inundating 250,000 ha and seriously affecting 2.7 million people.

Floods occur almost every year in the Red River delta in Vietnam causing large scale inundations leading to serious damages and loss of human lives. The most serious recorded flood occurred in 1971 when more than 500 people were killed, approximately 2.71 million people and 250,000 ha of land were affected. The estimated damage was approximately US$ 1 billion.