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Thirty years of major flooding in the U.S.

The flooding in Houston brought on by Harvey has proved to be catastrophic, but the region is no stranger to flooding. Here's a deep look at where major flooding events have occurred in the U.S. since 1985 using data from the Dartmouth Flood Observatory. Each shape represents the extent of a region affected by flooding, and is colored by the severity of the flooding. The map doesn't yet include the extent of the flooding caused by Harvey because it is still being measured.

Why it matters: Climate scientists say extreme flooding events will become more common as the climate warms because storms will dump more rain and the sea levels will rise (already 2.6 inches globally between 1993 and 2014, per NOAA).

Data: Dartmouth Flood Observatory; Map: Lazaro Gamio / Axios