By Victoria Gill BBC News, New Orleans
Image copyright Getty Images Image caption During Hurricane Harvey, Port Arthur in Texas experienced some the most extreme impacts of flooding
Scientists and engineers have teamed up across the Atlantic to “redraw” the flood map of the US.
Their work reveals 40 million Americans are at risk of having their homes flooded – more than three times as many people as federal flood maps show.
The UK-US team say they have filled in “vast amounts of missing information” in the way flood risk is currently measured in the country.
They presented the work at the 2017 American Geophysical Union meeting.
This mapping project includes areas across the US that are on river floodplains and those at risk of flash floods associated with heavy rainfall.
It focuses on rivers and does not include areas at risk of coastal flooding.