The 1931 Huang He floods (Yellow River Floods)are generally thought to be the deadliest natural disaster of historic times, and almost certainly of the twentieth century (when pandemics are discounted). Estimates of the number of people killed range from 850,000 to 4,000,000.

The Huang He or Yellow River has been prone to flooding due to the broad expanse of almost flat land around it. The 1887 Huang He floods had devastated the area, killing 900,000-2,000,000.

Later in the same month, the Yangtze also flooded.

1931 was the last natural flood of the river of this severity. In 1933, around 18,000 people were killed by less devastating, but still widespread flooding, while the 1938 flood was caused by Nationalists deliberately damaging levees in an attempt to disrupt Japanese advances.