High-res mapping of U.S. flood risk triples the population in harm's way

Some 41 million Americans are at risk of seeing their homes flooded in so-called 100-year events, an exposure level perhaps three times higher than the official estimates of the Federal Emergency Management Agency and other government bodies.

This is the marquee finding, but hardly the only surprise, in a groundbreaking study by researchers in Britain and the United States, including two scientists for The Nature Conservancy who work out of the group’s Minneapolis office.

The results are derived from modeling based on extraordinary advances in high-resolution mapping and supercomputing, in techniques developed at England’s University of Bristol and a nearby research institute called Fathom.

The new modeling has been applied globally for a number of Fathom's public and private clients, and in this instance sought to make improvements over “past attempts to estimate rainfall-driven flood risk across the U.S. [that] either have incomplete coverage, coarse resolution or use overly simplified models of the flooding process.”