Outdated maps fail to account for climate change; 1/3 of La. flooding outside marked floodplain

Outdated Federal Emergency Management Agency flood maps fail to account for climate change, Christopher Joyce reports for NPR. FEMA updates its flood-insurance maps every five years. "People with federally backed mortgages in the highest risk areas have to get flood insurance," Joyce notes. "People outside those areas don't."

That's become a problem in some areas, such as Louisiana, where Gov. John Bel Edwards' office has estimated that last month's flooding damaged 60,646 houses. FEMA says 109,398 people or households have applied for housing help and 25,000 National Flood Insurance Program claims have been filed," Drew Broach reports for The Times-Picayune in New Orleans. An estimated 18,873 houses were damaged by the flood and 50,750 people were caught in the flood or lived in a flooded home, according to DisasterMap.net. (Image: Extent of flooding last month in Baton Rouge)

"Satellite photos show that about a third of the flooding in Louisiana last month was outside the local flood plain," Joyce writs. "The flood plain is the area that historically gets inundated by a once-a-century flood." Nicholas Pinter, a geologist at the University of California, Davis, who researches floods said "floods that occur outside the historical flood plain appear to be happening more often — in Louisiana and elsewhere."

Kathy Schaefer, an engineer who spent 10 years drawing those maps at FEMA, told Joyce. "All of the mapping had to be based on the existing conditions (at the time they were drawn, or many years earlier)." She said "those conditions were rainfall and flooding statistics from the past. Sometimes decades in the past."