Increasing Numbers of U.S. Residents in High-Risk Wildfire and Flood Zones Millions of Americans are living on properties that are at-risk for climate change-related disasters. The solution to the problem is far more complicated than just telling residents to move. Anuradha Varanasi, Earth Institute | February 4, 2021 | Analysis The U.S. Federal Emergency Management Agency (FEMA) estimates that around 13 million Americans are living within a 100-year flood zone. But over the last few years, researchers have found that the government’s estimates are far lower than the ground realities. A 2018 study published in the journal Environmental Research Letters states that, taking into account the risk of flooding from rivers, about 41 million people are exposed to flood risk. That roughly equals three times more than FEMA’s estimates of residents who live in areas with a 1 percent chance of floods striking during any year.