Short answers, pulled from the story.
The 1931 China floods claimed between 2.5 million and 3.7 million lives, making it the deadliest natural disaster in recorded human history. This catastrophe was not merely a weather event but a convergence of monsoon rains, melting snow, and the failure of the Yellow River's levees, which had been maintained for centuries.
The 1938 Yellow River flood was caused by the intentional breaching of the river's levees by the Chinese government as a deliberate act of war to stop the advance of the Japanese army. This event resulted in the deaths of between 500,000 and 700,000 people and caused widespread destruction and suffering.
The 1975 Banqiao Dam failure resulted in the deaths of approximately 86,000 people from flooding and another 145,000 from subsequent disease. The dam, located on the Ru River in Henan Province, China, failed under the pressure of Typhoon Nina's heavy rains.
The 2004 Indian Ocean tsunami was caused by an undersea earthquake that released a sudden burst of energy, creating a series of massive waves that swept across the Indian Ocean. The waves reached heights of up to 30 meters and resulted in the deaths of approximately 230,000 people.
The 1935 Yangtze River flood killed approximately 145,000 people and was caused by heavy rains and the melting of snow which led to the overflow of the river's banks. The floodwaters swept away entire villages, destroyed crops, and left millions of people homeless.