High tide flooding forecast into 2024
Coastal communities in eight locations along the East and West coasts experienced record high tide flooding last year — a trend that is expected to continue in 2024. For many communities, the expected strengthening of El Nino will bring even more high tide flood days.
The 2023 Annual High Tide Flooding Outlook documents high tide flooding events from May 2022 to April 2023 at 98 NOAA tide gauges along the U.S. coast. It also provides a flooding outlook for these 98 locations through April 2024 and decadal projections out to 2050.
High tide flooding is becoming increasingly common due to continued sea level rise, driven in part by climate change. It occurs when tides reach anywhere between 1 to 2 feet above the daily average high tide, depending on location. As sea level rise continues, it no longer takes severe weather to cause disruptive flooding along the coast.
NOAA predicts that from May 2023 to April 2024 the U.S. will experience between four to nine high tide flood days — an increase from last year’s prediction of three to seven days and about three times as many than typically occurred in 2000.
This year, the expected strengthening of El Nino could further amplify high tide flooding frequencies along the East and West coasts. Communities on the Mid-Atlantic and Gulf coasts are expected to experience the most high tide flooding, as El Niño conditions will compound the effects of sea level rise in some areas.
For the Mid-Atlantic, nine to 15 days are predicted, an almost 350% increase since the year 2000. Along the western Gulf, seven to 14 days are predicted, an almost 350% increase since the year 2000.
For the Pacific Northwest, four to 11 high tide flood days are predicted — approximately a 150% increase over the year 2000, and for the Pacific Southwest, one to five days are predicted, an almost 100% increase since 2000.
By 2050, the nation is expected to experience an average of 45 to 85 high tide flooding days per year. Long-term projections are based on the ranges of expected relative sea level rise of about a foot, on average, across the United States by 2050. Data specific to each NOAA tide gauge can be found on the Annual High Tide Flooding Outlook website.