NOAA anticipates more frequent high-tide flooding

Martha’s Vineyard has been making its own preparations for rising sea levels and floods.

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According to Ross Seavey, the town's building commissioner, flooding last Wednesday afternoon on Beach Road was unrelated to any town water lines. It was groundwater, also known as sunny day flooding. -George Brennan

The National Oceanic and Atmospheric Administration (NOAA) announced during a recent press conference it expects higher frequencies of high-tide flooding in the U.S. William Sweet, an oceanographer with NOAA’s National Ocean Service, said there was a “record-breaking” amount of high-tide flooding, otherwise called “nuisance” or “sunny day” flooding, across the U.S. over the past year, bolstered by rising sea levels. Travelers on Beach Road in Vineyard Haven on Wednesday, August 3, witnessed such a phenomenon, as town officials told The Times that the flooding was unrelated to any town water lines, but instead was “groundwater.” 

In February, NOAA released its sea level rise technical report, titled “Global and Regional Sea Level Rise Scenarios for the United States,” which stated a forecast that the U.S. will experience up to a foot of sea level rise by 2050.

“That is to be expected to continue into next year, and into the foreseeable future,” Sweet said about the high-tide flooding. He defined high-tide flooding as when “tides reach anywhere from one-and-three-quarters feet to two feet above the daily average high tide, causing water to spill in the streets or bubble up from storm drains.” Sweet said high-tide flooding that happened only during storms “decades ago” occurs more frequently, even on days without “severe weather,” such as full-moon tides, or during changes in the wind and currents. 

NOAA reviewed 97 towns and cities for high-tide flooding. Across these areas, Sweet said, the rate of flooding is twice as high as around 20 years ago. The northeast Atlantic saw on average eight high-tide flooding days. 

“Sea level impacts are happening now and are growing rapidly, which is complicating preparedness planning,” Sweet said. However, he said the high-tide flood day outlooks can help decisionmakers better prepare their communities for these disruptive events. “This data can help communities plan where to put buildings, and how to build them to keep people safe. As towns, states, and the federal government, along with the public, increasingly consider the impacts of coastal inundation and related hazards, NOAA’s National Ocean Service is the authoritative source of data and information on a wide range of risks. We’re not just a data provider. Many of our people and facilities are actually located in the coastal zones, so we’re actually a truly vested partner at the center of the national conversation on sea level rise.” 

Sea level rise isn’t the only climate-related phenomena with a potential impact on Martha’s Vineyard. Starting in July 2021, the moon’s “wobble” is expected to create higher high tides and lower low tides over the next two decades. At the moment, Sweet said, the lower low tides from the moon wobble “helped to put the foot off the accelerator” for flooding. 

Although Martha’s Vineyard towns were not a part of the data set NOAA released, Woods Hole and Nantucket were shown on an interactive map to have experienced high-tide flooding four and five times respectively in 2021. NOAA predicts both towns will experience three to seven days of high-tide flooding in 2022. This steady increase in high-tide flooding in Woods Hole and on Nantucket can be seen when, comparatively, both towns saw only two high-tide flooding days in 2000. NOAA’s forecast has Woods Hole potentially experiencing 45 to 75 high-tide flood days, and Nantucket potentially experiencing 40 to 70 high-tide flood days, in 2050. 

These towns’ environmental similarities to Martha’s Vineyard means the Island cannot simply ignore these forecasts, even if M.V. itself was not a part of the study. Additionally, the high tide levels of Martha’s Vineyard towns are not too far off from Nantucket and Woods Hole. According to NOAA’s tide forecast of Wednesday, August 3, to Thursday, August 4, Oak Bluffs experiences between 1.64 feet and 1.84 feet of high tide, and Edgartown experiences between 1.94 feet and 2.31 feet of high tide. Woods Hole is not far off, forecast to experience between 1.78 feet and 2.13 feet of high tide. Nantucket’s forecast is higher, at between 3.08 feet and 3.45 feet of high tide. 

Ben Robinson, Martha’s Vineyard Commission member and an Island climate change leader, told The Times the Island has been preparing for rising sea levels and potential floods. A couple of examples include working with the Center for Coastal Studies in Provincetown to study the Island’s storm tide pathways, and the Seaport Economic Council grant Chilmark received to replace and elevate the fishing docks at Menemsha Harbor. 

“We are being proactive about it,” Robinson said. Other considerations include what happens to structures in low-lying areas and near the Island’s salt marshes (e.g. putting up structures on stilts, removing structures). 

Martha’s Vineyard experiences flooding from coastal storms, heavy rain, and nor’easters, but Robinson said high tides can cause flooding as well in areas closer to the ocean. Edgartown’s Dock Street and Menemsha have experienced flooding from high tide before. Robinson also said he expects some flooding to occur on Friday, August 12, and Saturday, August 13, which is when astronomical high tide is predicted to occur. On those days, NOAA’s forecasts have Oak Bluffs experiencing between 2.19 feet and 2.42 feet of high tide, and Edgartown experiencing between 2.12 feet and 2.93 feet of high tide.  

“If we think about our planning horizons from 2050 to 2070 and forward, simple solutions along places like the waterfront commercial district in Tisbury will be exhausted,” Robinson said. “You won’t be able to just raise your building and raise the land, because the sea level rise would be to a point where those solutions aren’t really going to be successful. We’re going to have to think more strategically about how much [we] retreat, what sort of things can survive in those areas, how much fill do we have to put in to keep things dry.” 

Robinson said climate change consequences, such as glacial melting in places like Greenland or Antarctica, and heating oceans, contribute to rising sea levels, although at different rates and effects globally.

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

6 COMMENTS

  1. I am certain MV will still be here in 20 years, but taxes for badly planned schools will continue and housing crisis will still be mentioned and NIMBY will still occur and lots of old people will leave because they can no longer afford to live here, and the usual suspects will clamor about fauna and flora and impending doom from climate but one person who hates fossil fuel will be gone. One ex President will still be here and his home in great shape.

    • andy– you are correct about that ex president’s home.
      Reputable scientist have been keeping us well informed about the rate of sea level rise since the 90’s. Yes, they have been off by quite a bit. In the 90’s they were saying that the worst case scenario was about 4 ft but the end of this century. Now they are saying about 6 ft.for the worst case scenario.
      Obama knows that. His house is currently 12 ft above sea level.
      It is the flood plain for hurricanes though..

      I see a lot of climate deniers criticize Obama for buying a house “on the beach” when he thinks it will be underwater in 20 years. He does not.. I wonder what the residents of Miami think about that 6 ft rise in sea level? The average elevation of Miami is 6.5 ft.
      Virtually all of Florida is experiencing more frequent and more damaging sunny day flooding events. You gotta be nuts to buy property along florida’s coast.

  2. Keller, My house on Hutchinson Island in Florida on the beach where I swim with sharks who only bite Democrats. Not worried a bit.

  3. Climate change is real. Throwing billions of dollars at it thinking we can impact it is foolish and naive. Conserve what we have and be good stewards for future generations. We can’t tell if it’s going to rain two weeks from now but somehow we know what the climate will be 20 years from now? Not buying it. Will the climate be different in 100 years? Yes. To what degree (pun not intended) nobody knows.

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