Researchers found that millions more Americans are threatened by flooding than suggested by government estimates.
A nonprofit research and technology group known as the First Street Foundation used a new model to assess flood risk and found that 70% more properties in the U.S., or 14.6 million properties, face substantial risk for flooding.
The group said its model differs from FEMA’s because it uses current climate data, maps precipitation as a stand-alone risk and includes areas that FEMA has not mapped.
“In environmental engineering, there is a concept called stationarity, which assumes that today is going to be like yesterday, and tomorrow is going to be like yesterday,” said First Street Foundation’s chief data officer Ed Kearns. “This concept used to work, but with a changing environment it’s a poor assumption and no longer does. FEMA’s method assumes stationarity, First Street’s does not.”
Since 1895, the average annual precipitation in Indiana has increased by 5.6 inches, or about 15%, and is projected to continue to rise.