ESTIMATEDDate confidence: ESTIMATEDA target, not a fixed dateHow firmly the source words the date: confirmed, scheduled, estimated, delayed or unverified.Show all ESTIMATED pins50% CONFIDENCEOverall confidence: 50%How well the pin's source and references back up its dates.Weighted average of how firmly 1 reference, the source included, supports the pin's start and end times; a reference counts half as much for every 180 days older than the newestShow all pins from 50% to 74% confidenceThe source[1] bounds the flooding by month rather than by day — "a series of devastating floods that occurred from June to August 1931" — so the pin spans 1 June to the end of August, with the one firm date inside it being the Lake Gaoyou dike breach of 25 August 1931.
Months of flooding along the Yangtze and Huai rivers inundated Wuhan, Nanjing and beyond, culminating in a dike breach at Lake Gaoyou on 25 August. Estimates of the dead run from 150,000 drowned to two million in total.
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