More flooding at high tide expected as sea level continues to rise
The incidences of dramatic flooding are increasing along the US coast, with the most dramatic increase along the Southeast Atlantic and Gulf coasts.
(CN) – High tide flooding, also known as ‘harmful’ flooding or ‘sunny days’, has doubled along the US coast from similar flooding twenty years ago and is expected to continue to increase, according to a new report. government report.
Between May 2020 and April 2021, coastal communities along the United States experienced twice as many high tide flooding as in 2020, especially along coastal areas along the Atlantic coast and the Gulf. from Mexico, according to a report released Wednesday by the National Oceanic and Atmospheric Administration. , 2021 State of floods at high tide and annual outlook. The trend is expected to continue in 2022.
The report documents the evolution of high tides and flood patterns over the past year on 97 NOAA tide gauges along the US coast, and provides flood outlook for these locations through April 2022 as well. as projections for the next decades.
“High tide flooding is becoming common and damaging in many parts of the United States,” William Sweet, oceanographer for the National Ocean Service of NOAA and lead author of the report, said Wednesday in an emailed press release. “Many coastal communities face this problem, so NOAA is working to provide them with the types of information needed to anticipate, prepare for and respond to the increasingly frequent flooding at high tide. “
The study showed that during the period 2020-2021, 14 sites along the Southeast Atlantic and Gulf coasts, matched or broke their records for the number of days of flooding – an increase from 400 to 1,100% compared to what was recorded in 2000, according to the report. . The number of high tide flood events is currently accelerating at 80% of NOAA water level stations along these coasts.
Flooding at high tide, or what is defined by NOAA as “flood that causes inconvenience to the public”, causes flooding of shores, streets and basements, obstructions to traffic and the cancellation of events.
The term “high tide flooding” refers to incidents when the tides reach 1.75 to 2 feet above the daily average high tide and begin to spill into the streets or bubble from storm sewers.
The impacts of such flooding, which decades ago only occurred during storms, become more and more frequent during full moon tides and the prevailing winds and currents change as the level of the sea level. sea continues to rise.
“NOAA tide gauges show that 80% of the places where we collect data along the Southeast Atlantic and Gulf coasts are experiencing an acceleration in the number of flood days,” said Nicole LeBoeuf, director of the NOAA’s National Ocean Service, in an emailed press release.
“Flooding at high tide disrupts people’s lives when they can’t get to or from work or have to repeatedly deal with a flooded basement,” LeBoeuf continued. “NOAA is committed to working with coastal communities to provide the information and tools they need to tackle the problem of high tide flooding, both now and in the years to come, as the level the sea continues to rise.
Areas of particular concern, according to the data, are in Texas and Florida, with records also broken along the South Carolina and Georgia coasts.
During the relevant period, Galveston and Corpus Christi, Texas, and Bay Waveland, Mississippi each set a record of over 20 days of high tide flooding. Twenty years ago, according to the report, these areas would have typically only experienced 2-3 days each.
Dauphin Island, Alabama; Grand Isle, Louisiana; Pensacola, Panama City Beach and Trident Pier, Florida; Charleston, South Carolina; Port Isabel and Rockport, Texas all experienced between 10 and 20 days of flooding. In 2000, they would have experienced between 0 and 2 days of flooding at high tide.
The study authors project that from May 2021 to April 2022, the national frequency of high tide flooding is expected to continue to increase, with U.S. coastal communities experiencing an average of 3 to 7 days of flooding during the year to to come, compared to last year’s projection of 2-6 days. Places along the Atlantic and Gulf coasts may experience even more flood days.
By 2030, projections indicate 7 to 15 days of flooding per year in national coastal communities, and by 2050 the forecast increases to 25 to 75 days per year.
Long-term forecasts are based on the range of relative sea level rise, using two scenarios, low intermediate and intermediate, from the Fourth National Climate Assessment considered more likely to occur by now 2030 and 2050.
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