Sunny skies, no storm in sight—and yet, the street is underwater. New research shows this isn’t an anomaly, but a growing reality in coastal towns.
Key Points at a Glance
- Traditional flood monitoring tools drastically underestimate real flood frequency
- Land-based sensors reveal floods on up to 128 days a year in some towns
- More accurate data can guide smarter infrastructure and climate policy
- Floods are lasting longer than tide gauge data suggest
Imagine waking up on a sunny day, only to find your street submerged in water—not because of a hurricane or major storm, but because of the rising sea. That’s the new normal for many coastal communities in North Carolina, according to a groundbreaking study from researchers at North Carolina State University and the University of North Carolina at Chapel Hill. And it’s happening far more frequently than anyone expected.
Led by Dr. Miyuki Hino and Dr. Katherine Anarde, the research team discovered major discrepancies between actual flood events and the predictions made using traditional tide gauge methods. These tide-based thresholds, long used by agencies like NOAA and the National Weather Service, are shown to underestimate both the frequency and duration of flooding in vulnerable regions. The solution? Land-based sensors that tell the true story.
Deployed across the towns of Beaufort, Carolina Beach, and Sea Level, these new sensors monitored road-level flooding over a full year. The results were eye-opening. In Sea Level, for instance, flooding was recorded on 128 days—compared to just nine days when using NOAA’s High Tide Flooding threshold, and 31 days by the NWS minor flood threshold. Even more surprising: the NWS method sometimes overestimated flooding in other towns, such as Carolina Beach.
“Sea-level rise has changed the flooding landscape,” says Anarde. “We’re seeing floods from high tides and ordinary rainfall—not just big storms. The methods we use to measure and predict floods must evolve to reflect this reality.”
The duration of floods was another area where traditional data fell short. While tide gauges can show when water levels rise, they don’t accurately reflect how long it takes for floodwaters to recede. This lag can be critical when planning emergency response or evaluating infrastructure needs.
What’s at stake is more than academic accuracy. Real-time, precise data is vital for local governments and residents alike. It determines whether roads are safe, whether buildings need to be elevated, and where adaptation investments should go. Misjudging the scope of flooding leaves communities vulnerable and unprepared.
“More accurate flood monitoring helps target the right solutions,” says Hino. “And it’s not one-size-fits-all. Each town faces its own challenges, and data helps tailor responses to those specific needs.”
The study, published in Nature Communications Earth & Environment, is part of the Sunny Day Flooding Project—an initiative aimed at improving the science and strategy behind coastal flood resilience. It’s already helping reshape how communities assess their risk and prepare for a wetter future.
With support from multiple institutions including the U.S. Department of Homeland Security, NOAA, NASA, and the National Science Foundation, the research team is now working directly with local governments to apply their findings on the ground.
As climate change continues to raise sea levels and reshape coastlines, understanding when, where, and how often flooding occurs is no longer optional—it’s essential.
Source: NC State News
