High-tide flooding (HTF) broke or tied records in three locations in U.S. coastal areas in the past year, according to data released Tuesday by the National Oceanic and Atmospheric Administration (NOAA). 

HTF has become increasingly frequent across the country but will likely decline this year, according to NOAA. The administration attributed the decrease to the La Niña weather phenomenon.

HTF increases are likely to be concentrated along the East Coast and Gulf of Mexico, where NOAA is predicting a 150 percent increase from the year 2000.  

Since May of this year, three different NOAA-monitored locations have tied or broken previous records for number of HTF days. Reedy Point, Del., saw a new high of six events, while Kwajalein Island in the Pacific broke its 2021 record with four days of HTF. Meanwhile, South Carolina’s Springmaid Pier saw 11 HTF events, tying its 2021 high. 

HTF occurs when ocean water floods into low-lying areas during high-tide periods, usually following tides of between 1.75 and 2 feet above the daily average. In years past, these events have been limited to storms, but they have recently become common during prevailing-wind changes or even full moons.  

The aftereffects of the La Niña event will likely blunt HTF along the West Coast and in the U.S.’s island holdings, but levels are likely to be higher along the East Coast and the western and eastern Gulf coasts, according to NOAA. 

HTF is likely to become far more extreme on a national scale in the decades ahead, according to NOAA. By 2050, NOAA predicts HTF at a national scale for about 45 to 70 days per year on average, an estimate based on projected sea level rise data. 

“Coastal flood warnings for significant risks to life and property, will become much more commonplace as we approach mid-century,” NOAA officials said.