The State of High Tide Flooding and 2022 Outlook

Last week, the National Oceanic and Atmospheric Administration (NOAA) released its “State of High Tide Flooding and 2022 Outlook,” which highlights changes in high tide flooding patterns from May 2021 to April 2022 at 97 NOAA tide gauges along the U.S. coast. It also provides a flooding outlook for these locations through April 2023 and forecasts for the next several decades.

High tide flooding is becoming increasingly common due to continuing sea level rise, which is driven in part by climate change. According to NOAA, “High Tide Flooding (HTF) is defined as the overflow or excess accumulation of ocean water at high tide that covers low-lying areas, and typically occurs when tides reach anywhere from 1.75 to 2 feet above the daily average high tide and start spilling onto streets or bubbling up from storm drains. As sea level rise continues, damaging floods that happened decades ago only during a storm now happen more regularly, like during a full-moon or with a change in prevailing winds or currents.” Some of the key projections in NOAA’s outlook report include HTF frequency between May 2022 and April 2023 will average 3-7 days, the same as the previous year, but an increase from the 2-6 days expected between 2019 and 2020. Regional locations such as the Northeast Atlantic, Western Gulf, Southeast Atlantic and Eastern Gulf coasts may see some of the highest levels of HTF. And by 2050, high tide flooding on a national scale is expected to be between about 45 – 70 days/year on average. Access the Outlook here or read a relevant news article here.