High Tide Flooding: How will the flooding outlook be in coming years?

Coastal communities across the U.S. continued seeing record-setting high-tide flooding in 2019 (Representative image/ Reuters)

High-tide flooding is increasingly becoming common due to years of relative sea level rise. It is often referred to as “nuisance” or “sunny day” flooding as well. High flooding occurs when tides reach anywhere from 1.75 to 2 feet above the daily average high tide and the water starts spilling onto the streets or bubbling up from storm drains. As sea level continues to rise, damaging floods which used to happen only during a storm now happen more regularly, such as full-moon tide or with a change in prevailing winds or currents.

Every year, NOAA (National Oceanic and Atmospheric Administration) records changes in high-tide flooding patterns from the previous year at 98 NOAA tide gauges along the U.S. coast which helps provide a flooding outlook for these locations for the coming year, as well as projections for the next several decades.

Check out the state of High Tide Flooding in 2019 and its outlook through April 2021

Coastal communities across the U.S. continued seeing record-setting high-tide flooding in 2019. It forced their residents and visitors to deal with flooded streets, shorelines and basements. Also, it indicates that the trend is expected to continue this year as well (2021) and not abating anytime soon.

1. The national annual flood frequency reached 4 days in 2019–just shy of the record of 5 days set which was set in 2018. High tide flooding is now accelerating at 75 per cent of locations along the East and Gulf Coasts. As many as 19 locations broke or tied their flood records.
2. The National high tide flood frequency is expected to accelerate. U.S. coastal communities are witnessing an average of 2-6 days of flooding in the coming year. Also, the communities along the northeast and western Gulf coasts will this time see higher levels of floods. No high frequency flood, however, is predicted for the US. island coastlines.
3. It is also said that by 2030, high tide flooding is likely to be in the range of 7 – 15 days and between 25 – 75 days by 2050. These projections have been made based on the range of relative sea level rise which is more likely to occur by 2030 and 2050 using the Fourth National Climate Assessment.