Flood maps omit 13 million high-risk properties

Almost 13 million properties rated as highly vulnerable by First Street fall beyond FEMA’s Special Flood Hazard Areas. A federal watchdog highlighted the gap. FEMA’s boundaries focus mainly on river and coastal threats, while intense rain can overwhelm soil and drainage systems, sending water into streets and houses far from waterways.

Insurance coverage differs sharply across the boundary. As of April, 43% of properties within FEMA’s designated areas had National Flood Insurance Program policies, versus 2% beyond them. The watchdog also found that low-risk properties inside the mapped areas were more likely to have federal coverage than even the most exposed properties outside. FEMA considers a wider range of hazards when calculating premiums, but those factors do not necessarily place a property in an area where coverage may be required.

The gap could become more consequential during the anticipated El Niño. NOAA put the likelihood of a very strong event above 90%, with unusually wet conditions favored across much of the South. Researchers reviewing claims from 1978 through 2017 found that insured damage in Southern California was 10 times higher during El Niño winters than during La Niña winters. A small number of severe storms drove much of the loss across the Western states examined.