August 25 edit
1635: A major hurricane struck southeastern New England, killing more than 46 people.
1931: The Grand Canal broke through dikes near the city of Gaoyou, China, drowning more than 2,000 people. This was just one tragedy in a large series of floods that year which killed hundreds of thousands of people by drowning, disease, and starvation.
1986: The remnants of Hurricane Charley passed just south of Ireland, causing record rainfall and major flooding which killed four people.