A woman walks along a street flooded by high tides in Miami Beach, Florida in 2019. Sunny-day flooding is becoming more common in many coastal areas as sea levels rise due to human-caused climate change.
Lynne Sladky/AP/AP
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Lynne Sladky/AP/AP
Coastal flooding from high tides is becoming more common in most areas of the United States as climate change causes sea levels to rise.
Millions of people are affected by so-called sunny day floods every year, according to a new report According to the National Oceanic and Atmospheric Administration (NOAA), the United States now experiences an average of five more days of high tide flooding each year than it did in 2000.
“Over the past year, we have seen record coastal flooding,” said Nicole LeBoeuf, director of the NOAA National Oceanic and Atmospheric Administration.
Last year, St. Petersburg, Fla., Atlantic City, N.J., Charleston, S.C. and more than 30 other places tied or broke their records for the number of days flooded by high tides. Galveston, Texas, which consistently saw several severe and frequent flooding due to high tides of any city in the United States experienced 23 days of tidal flooding last year.
The costs of flooding from high tides are huge. Even a few inches of water can make neighborhoods inaccessible to some residents, including those who use wheelchairs or rely on strollers to pick up and drop off small children. And standing water can also block walkways, blocking ambulances and causing secondary flooding if sewage overflows into buildings or into natural water sources.
“People who live in [Florida] “The Keys or Annapolis or Norfolk — they’re facing traffic delays getting their kids to school or getting to work because of water flooding the streets,” said Karen Kavanaugh, an oceanographer at NOAA. Flooding from high tides can also force businesses to close, and even small amounts of saltwater can erode underground pipes and damage vehicles.
Sea level not increasing at the same rate everywhereand the impact of high-tide flooding is even more pronounced in places where sea levels are rising most rapidly, the report notes. Over the past 25 years, the number of days with high-tide flooding has increased by 250% or more in many areas, including along the Gulf of Mexico, and in the Mid-Atlantic and Pacific Islands.
“Decades of sea level rise is having an impact,” said William Sweet, an oceanographer at NOAA.
And there is no relief in sight as global temperatures continue to rise and sea levels continue to rise. The average annual number of high-tide flooding days in the United States is expected to exceed 45 by mid-century. Local governments in many coastal areas are racing to upgrade infrastructure to withstand saltwater, improve sewer and drainage systems, and budget for the cost of damage and disruption from high-tide flooding.
While high tide flooding forecasts don’t account for storm surge flooding, rising sea levels that cause more flooding on sunny days also exacerbate coastal storm surge flooding, as residents of Florida, Georgia and South Carolina Aftermath of Hurricane DebbyThe storm made landfall in Florida as a weak Category 1 hurricane and quickly weakened to a tropical storm, but storm surge and rain still caused catastrophic flooding across the Southeast, in part because rising sea levels brought ocean deposits closer to the coast.
“These areas are already being impacted by rising sea levels, making the combination of Debby and the rainfall potentially catastrophic,” LeBoeuf explained.
