Floods happen for many reasons. Heavy rains, large amounts of snow melt, ocean waves, and breaking levees and dams are common causes of flooding. A ton of water is not necessary to cause flood damage. Just a few inches may be enough to require extensive reconstruction of a building. On top of that, flood waters can be incredibly powerful, sweeping entire buildings off their foundations. In fact, deadly floods kill more people each year than tornadoes, hurricanes, or lightning strikes.
Floods are especially dangerous because they can happen fast. During flash floods, waters may rise in a matter of minutes. People in the flood’s path do not have much warning. For example, a mountain stream that is normally a few inches deep can turn into a 10-foot-deep river in less than an hour in the right weather conditions. Several of the deadliest floods in recorded history have occurred in China, where several rivers coexist alongside large populations. Let’s check out the six deadliest floods of all time.
1. 1931 China Floods
This set of floods is also referred to as the 1931 Yangtse-Huai River Floods. After a drought from 1928-1930, the area of the Yangtse and Huai Rivers received heavy snowfall. When it started to melt in early 1931, the extra water flowed down the river, along with still melting ice and snow. Then, heavy continual rains for months caused the rivers to rise even more. Starting in June, people living in low-lying areas had to evacuate due to flooding. Then, on July, 9 cyclones hit the region, adding more rainfall. The area received 2 feet of rain in one month. This caused massive flooding the size of the country of England (approximately 69,000 square miles.) It severely affected eight different provinces, with more moderate effects in many others.
Overall, 150,000 people died as a direct result of drowning in the floods. However, an additional two million people reportedly died due to lack of food and necessities. The following year, the flood caused a cholera outbreak, a bacterial illness caused by drinking dirty water, which people in the affected area were likely doing since they lacked access to resources. Up to 100,000 additional deaths were caused by this outbreak. Some estimates put the total number of deaths from this months-long flood at nearly four million.
The flood waters receded in August; however, due to even more rain, some of the area’s rivers did not go back to normal until November of 1931. Between 25 and 50 million people were affected by the flooding. Sadly, about 15% of the area’s important wheat and rice fields were destroyed.
2. 1887 Yellow River Flood
Over 900,000 people were killed in the 1887 flood on the Yellow River in China. Because Chinese farmers built dikes along the river to protect their crops, the river could not naturally deposit silt, causing the overall water level to rise.
This flood affected over 50,000 square miles. Two million people lost their homes. It is estimated that an additional 900,000 people died after the floods due to a lack of access to food, clean water, and healthcare. Overall, experts estimate that at least three million people died from this flood.
3. 1938 Yellow River Flood
In 1938, the Chinese military opened up levees on the Yellow River to prevent the advancement of the Japanese army, which had taken control of Northern China. Though exact numbers are unknown, many Japanese soldiers died in the flooding. It is estimated that 800,000-900,000 people died in total. However, many government officials fled the war-torn villages, so official counts were not always completed.
The surrounding area was deeply affected for several years following the flood. The fields were covered in silt, so they were not as fertile. A lot of structures were destroyed. This is considered one of the most significant acts of environmental warfare to ever occur. The river did not return to its earlier course until 1947.
4. 1975 Banqiao Dam Failure
During Typhoon Nina, a category 3 storm, over a year’s worth of rainfall (about 3.5 feet) for the area fell in just one day on August 7, 1975. The damn had been built to withstand a “one in a thousand-year” rainfall event of about 1 foot. Due to the dam breaking, the People’s Liberation Army purposely destroyed other dams further downstream to control the flooding. Even so, dikes on the Quan River failed.
The resulting flooding caused anywhere from 85,000-240,000 deaths. Entire towns, like the Daowencheng Commune, were entirely wiped out. Due to the technology of the time and the weather conditions, warnings were not received or were miscommunicated. Many people in the area did not have a telephone so signals were attempted via telegraph and flares. People spreading warnings often got caught up in the floods.
The Chinese government lists the official death toll as 26,000. They also initially covered up this event. For over 12 years, no one outside of China knew about this catastrophe. They did not allow the media to make any reports. However, in 1987, a Chinese journalist wrote a book about the floods. In 1995, the Henan Daily, the newspaper for the area where the floods took place, published a story about what happened. Finally, in 2005, the government declassified the official documents relating to the dam failure.
5. 1935 Yangtse Flood
This event followed just a few years after the devastating 1931 floods in the region. Much of the infrastructure that had been rebuilt was damaged once again. And many of the measures that had been put in place to reduce flood risks were overcome.
A high number of typhoons off the coast of China may have created a sudden rise in the river on July 6, 1935. Several levees broke, and other areas became flooded when the river spilled over its banks.
Over 140,000 people died as a result of the flood. Even more died afterward from starvation. The previous year had seen a drought, which meant there were fewer crops than usual. This flood affected over 5,500 square miles of farmlands, further reducing the available food in the area. Others died from diseases that spread as a result of the flooding.
6. 1530 St. Felix’s Flood
The 6th deadliest flood in the world happened on November 5, 1530, in The Netherlands. Another name for this flood is Evil Saturday or Bad Saturday. Estimates put the number of dead at 100,000.
It happened in the Dutch Province of Zeeland. Part of the area was reclaimed by the sea and could not be recovered. In 1532, another flood occurred in the area, destroying the recovery efforts from this 1530 flood. Because it happened so long ago, there aren’t many details available, but we do know it was devastating.
Summary of the 6 Deadliest Floods of All Time
|Estimated Death Toll
|1931 China Floods
|Up to 4 million
|1887 Yellow River Flood
|1938 Yellow River Flood
|1975 Banqiao Dam Failure
|1935 Yangtse Flood
|1530 St. Felix’s Flood
The photo featured at the top of this post is © swa182/Shutterstock.com
FAQs (Frequently Asked Questions)
What was the deadliest flood ever?
The 1931 Yangtse-Huai River Floods in China were the deadliest floods ever. As many as 4 million people died.
What causes floods?
Heavy rains, large amounts of snow melt, large ocean waves, and breaking levees and dams are common causes of flooding.
What is the 2nd deadliest flood ever?
Over 900,000 people were killed in the 1887 flood on the Yellow River in China.
Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.