Boston could face 18 high-tide flooding days over the next year and up to 70 days by 2050, according to new predictions as “sunny day” flooding becomes more common due to years of sea level rise amid climate change.
The city’s projected high-tide flooding days from May 2022 to April 2023 is 11 to 18 days, according to updated predictions from the National Oceanic and Atmospheric Administration on Tuesday.
That projection for Boston jumps to 50-70 high-tide flooding days in 2050. Some of the most common spots for high-tide flooding in the city include Long Wharf and Morrissey Boulevard.
“High tide flooding is becoming more common and damaging in many parts of the U.S.,” said NOAA Administrator Rick Spinrad.
“As part of NOAA’s work to build a Climate-Ready Nation, we will continue to provide coastal communities with the information needed to anticipate, prepare for and respond to increasingly frequent high tide flooding,” he added.
High-tide flooding is often referred to as “sunny day” flooding or “king tides.” The flooding is more common these days following decades of sea level rise driven by climate change. It 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 are expected to happen more regularly — such as during a full moon or with a change in prevailing winds or currents.
High-tide flooding conditions along the East Coast is accelerating, and coastal flood warnings are expected to become much more common in the decades to come.
“The East and Gulf coasts already experience twice as many days of high tide flooding compared to the year 2000, flooding shorelines, streets and basements and damaging critical infrastructure,” said Nicole LeBoeuf, director of NOAA’s National Ocean Service.
“As sea levels continue to rise, NOAA is committed to working with coastal communities to provide the tide gauge information and tools they need to tackle the problem, both now and in coming years,” LeBoeuf added.
Boston recorded seven high-tide flooding days in 2021. It was lower due to Earth’s place at the furthest proximity from the moon in a Perigean cycle.
By 2050, national scale high-tide flooding is expected to occur 45 to 70 days per year. Long-term projections are based on the ranges of expected sea level rise of about one foot on average across the country by 2050.
NOAA is continuing to improve its ability to predict high-tide flooding. NOAA maintains ocean observing infrastructure, including more than 200 permanent water level stations on the U.S. coasts and Great Lakes, and has been the nation’s source for historic and real-time data, forecasts, predictions and scientific analyses for more than 100 years.