Coastal flooding accelerating due to local weather change : NPR

Coastal flooding from excessive tides is getting extra frequent in most components of the USA, as local weather change causes sea ranges to rise.

Tens of millions of persons are affected by so-called sunny day flooding annually, in keeping with a brand new report by the Nationwide Oceanic and Atmospheric Administration (NOAA). On common, the U.S. now experiences 5 further days of high-tide flooding annually in comparison with the yr 2000.

“Over the past year we’ve seen record coastal flooding,” says Nicole LeBoeuf, the director of the NOAA Nationwide Ocean Service.

Within the final yr, St. Petersburg, Fla., Atlantic Metropolis, N.J., Charleston, S.C. and greater than 30 different locations tied or broke their data for the variety of high-tide flood days. Galveston, Texas, which persistently sees a number of the most extreme and frequent high-tide flooding of any metropolis within the U.S., skilled 23 days of high-tide flooding final yr.

The prices of high-tide flooding are monumental. Even a number of inches of water could make neighborhoods inaccessible to some residents, together with those that use wheelchairs or depend on strollers to move younger youngsters. And standing water may also snarl commutes, block emergency autos and trigger secondary flooding if sewers again up into buildings or overflow into pure our bodies of water.

“People living in the [Florida] Keys or Annapolis or Norfolk – they’re facing traffic delays dropping their kids off at school or getting to work because there’s water that’s flooding the streets,” says Karen Kavanaugh, an oceanographer at NOAA. Excessive-tide flooding may also drive companies to shut, and even a small quantity of saltwater flooding can erode underground pipes and harm autos.

Sea ranges don’t rise on the similar fee all over the place, and the consequences of high-tide flooding are much more pronounced in locations the place sea ranges are rising most quickly, the report notes. Within the final 25 years or so, the variety of days with high-tide flooding has elevated by a whopping 250% or extra in lots of areas, together with alongside the Gulf of Mexico, and within the Mid-Atlantic and the Pacific Islands.

“Decades of sea level rise are catching up,” says William Candy, an oceanographer at NOAA.

And there’s no reprieve in sight, as international temperatures proceed to extend and sea ranges proceed to rise. The common variety of annual high-tide flood days for the U.S. is predicted to high 45 days by mid-century. Native governments in lots of coastal areas are racing to improve infrastructure to face up to salt water, enhance sewers and drainage and price range for the prices of harm and disruption from high-tide flooding.

Whereas high-tide flood forecasts don’t think about flooding from storms, the identical sea stage rise that’s driving extra sunny day floods additionally exacerbates coastal storm flooding, as residents of Florida, Georgia and South Carolina skilled following Hurricane Debby. The storm got here ashore in Florida as a weak Class 1 hurricane and was rapidly downgraded to a Tropical Storm, however storm surge and rain has nonetheless triggered catastrophic flooding throughout the Southeast, partly as a result of rising seas imply the ocean is nearer to the built-up shoreline.

“These areas are already under the thumb of sea level rise, making the combination of Debby’s storm surge and rainfall potentially catastrophic,” LeBoeuf explains.