NOAA predicts more frequent high tide flooding

The National Oceanic and Atmospheric Administration (NOAA) announced at a recent press conference that it expects higher frequencies of high tide flooding in the United States. William Sweet, an oceanographer with NOAA’s National Ocean Service, said there was a “record” amount of tidal flooding, otherwise known as “nuisance” or “sunny day” flooding, across the United States during of the past year, enhanced by rising sea levels. Travelers on Beach Road in Vineyard Haven on Wednesday August 3 witnessed such a phenomenon, as city officials told The Times that the flood was not related to any city water pipes, but was instead “underground water”.

In February, NOAA released its Sea Level Rise Technical Report, titled “Global and Regional Sea Level Rise Scenarios for the United States,” which indicated a forecast that the United States United States would experience sea level rise of up to one foot by 2050.

“It’s expected to continue into next year and into the foreseeable future,” Sweet said of the high tide flooding. He defined high tide flooding as when “the tides reach between one foot and three-quarters and two feet above the mean daily high tide, causing water to spill into streets or upwell storm drains”. Sweet said high-tide flooding that only happened during storms “decades ago” happens more frequently, even on days without “severe weather,” like full moon tides, or during changes wind and currents.

NOAA examined 97 cities and towns for flooding at high tide. In these areas, Sweet said, the flood rate is twice as high as it was about 20 years ago. The northeast Atlantic experienced an average of eight days of flooding at high tide.

“Sea level impacts are happening now and increasing rapidly, making preparedness planning challenging,” Sweet said. However, he said the outlook for flood days at high tide can help policymakers better prepare their communities for these disruptive events. “This data can help communities plan where to place buildings and how to construct them to keep people safe. As cities, states, and federal governments, as well as the public, increasingly consider the impacts of coastal flooding and related hazards, NOAA’s National Ocean Service is the source for data and information authority on a wide range of risks. We are not just a data provider. Many of our employees and facilities are actually located in coastal areas, so we are a true partner at the center of the national conversation on sea level rise.”

Sea level rise isn’t the only climate-related phenomenon potentially impacting Martha’s Vineyard. From July 2021, the “wobble” of the moon is expected create higher high tides and lower low tides over the next two decades. For the time being, Sweet said, the lower low tides of the moon’s wobble “helped lift the gas pedal” for the floods.

Although the towns of Martha’s Vineyard were not part of the data set released by NOAA, Woods Hole and Nantucket were featured on a interactive map having experienced four and five high tide flooding days in 2021, respectively. NOAA predicts that both cities will experience three to seven days of high tide flooding in 2022. This steady increase in high tide flooding in Woods Hole and Nantucket may be observed when, comparatively, the two cities experienced only two days of flooding at high tide in 2000. According to NOAA forecasts, Woods Hole could experience 45 to 75 days of flooding at high tide, and Nantucket could experience 40 to 70 days of flooding at high tide in 2050.

These towns’ environmental similarities to Martha’s Vineyard mean the island cannot simply ignore these predictions, even though MV itself was not part of the study. Also, the high tide levels of the towns of Martha’s Vineyard are not too far from Nantucket and Woods Hole. According to the NOAA tide forecast for Wednesday, August 3 through Thursday, August 4, Oak Bluffs is experiencing between 1.64 feet and 1.84 feet high tide, and Edgartown is experiencing between 1.94 feet and 2.31 feet high tide . Woods Hole is not far away, should experience between 1.78ft and 2.13ft high tide. The Nantucket forecast is higher, between 3.08 feet and 3.45 feet high tide.

Ben Robinson, a member of the Martha’s Vineyard Commission and the island’s climate change leader, told The Times that the island was preparing for rising sea levels and potential flooding. Some examples include working with the Center for Coastal Studies in Provincetown to study the storm tide lanesand the Seaport Economic Council grant that Chilmark received for replace and raise fishing piers at the port of Menemsha.

“We’re proactive about it,” Robinson said. Other considerations include what happens to structures in low-lying areas and near the island’s salt marshes (eg, placing structures on stilts, removing structures).

Martha’s Vineyard suffers flooding from coastal storms, heavy rainand northeast, but Robinson said high tides can also cause flooding in areas closer to the ocean. Edgartown’s Dock Street and Menemsha were previously flooded at high tide. Robinson also said he expects flooding on Friday August 12 and Saturday August 13, when an astronomical high tide is expected. On these days, NOAA forecasts indicate that Oak Bluffs experiences between 2.19 feet and 2.42 feet high tide, and Edgartown experiences between 2.12 feet and 2.93 feet high tide.

“If we think about our planning horizons from 2050 to 2070 and beyond, simple solutions along places like Tisbury’s waterfront shopping district will be exhausted,” Robinson said. “You can’t just raise your building and raise the land, because sea level rise would be so much that those solutions wouldn’t really succeed. We’re going to have to think more strategically about how much [we] retirement, what kind of things can survive in those areas, how much backfill do we need to put in to keep things dry.

Robinson said the consequences of climate change, such as melting glaciers in places like Greenland or Antarctica, and warming oceans, are contributing to sea level rise, albeit at slower rates. and different effects globally.

“Sea level rise, although it’s slow and gradual…the rate at which it’s happening is increasing,” Robinson said. “It’s incredibly dynamic, and sea level rise just isn’t the same everywhere. The planet is not a perfect sphere, and sea level rise will be different in different places… but it is rising. We know that.”

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