A new study from North Carolina State University has found that the nation’s flood maps may be unintentionally encouraging new construction in areas highly susceptible to flooding. The researchers warn that development near the boundary of FEMA’s 100-year flood zone—also known as the special flood hazard area—has surged in recent years and is poised to continue.
Key Findings
- Analyzing data from 2,300 counties, the study found that up to 24% of development from 2001 through 2019 occurred within 250 meters of the official FEMA flood zone boundary.
- The delineation of “at risk” or “minimal risk” on FEMA’s maps can give property owners and developers a false sense of security if they build just outside the designated floodplain.
- In Beaufort County, North Carolina—impacted by Hurricane Florence—almost 2,000 flooded buildings were outside the special hazard area, which typically is labeled “minimal” flood risk on official maps.
Why This Matters
- Hurricanes Helene and Florence, particularly Helene in September 2024, revealed how storms can dump record-breaking rainfall on areas thought to be safe from flooding.
- In mountainous regions like western North Carolina, buildable land is often along stream networks, leading to higher concentrations of development close to flood-prone areas.
- Although FEMA introduced Risk Rating 2.0 in 2021 to better estimate risks within designated areas, it does not factor in properties that sit outside official flood zones—where development continues to flourish.
Looking Ahead
- The NC State researchers anticipate the trend of building near flood-prone zones to continue through 2060 unless policies change.
- They emphasize that the existing FEMA maps often do not account for intensifying rainfall events, nor do they address the impact of rising sea levels.
- Insurance agents and carriers continue to encourage property owners—even those outside the mapped zones—to consider flood insurance, given the increasing frequency and severity of flood events.
The recent study, published in the open-access journal PLOS One, underscores what critics of FEMA maps have argued for years: A line on a map does not always indicate true safety. As storms intensify and rainfall patterns shift, policymakers and property owners alike face growing pressure to rethink how, and where, new development should be allowed.