1931 Central Chinese Floods
Good article: http://floodlist.com/asia/central-china-floods-1931
Great Mississipi Flood 1927
In 1925, the word "tornado" wasn't even in the vocabulary of the U.S. Weather Bureau (now the National Weather Service). The word had been banned since 1887, when the U.S. Army Signal Corps managed the country's weather forecasting. Tornadoes were utterly unpredictable, the logic went, and forecasting them, besides being a fruitless venture, would only spread panic among the public. Forecasters weren't allowed to study tornadoes, or even acknowledge their existence in public.