Future sea level projections are provided for the Massachusetts coastline at established tide gauge stations with long-term records at Boston Harbor, MA; Nantucket, MA; Woods Hole, MA; and Newport, RI. The projections shown in this map layer are adjusted to each station’s mean sea level and converted to the North American Vertical Datum of 1988 (NAVD88).

The analysis for Massachusetts (DeConto and Kopp, 2017) consisted of a probabilistic assessment of future relative sea level rise at each tide gauge location given two future atmospheric greenhouse gas concentration pathways, medium (RCP4.5) and high (RCP8.5), and for two methods of accounting for Antarctic ice sheet contributions to sea level rise: one based on expert elicitation (Kopp, 2014) and one where Antarctic ice sheet projections are driven by new, process-based numerical ice sheet model simulations (DeConto and Pollard, 2016; Kopp, 2017). A multi-year reference time period for relative sea level was used to minimize biases caused by tidal, seasonal, and inter-annual climate variability, following the accepted practice of using a 19-year tidal datum epoch centered on the year 2000 as the ‘zero’ reference for changes in relative sea level rise. To account for the ‘zero’ reference point utilized for the models and to provide elevations on a common geodetic datum, sea level rise model projection values at each tidal station were adjusted to the station’s mean sea level as computed for the 19 year tidal datum epoch of 1999-2017 and converted to NAVD88.

Following the approach in the 2017 National Climate Assessment and the National Oceanic and Atmospheric Administration’s Global and Regional Sea Level Rise Scenarios for the United States, conditional probability distributions for sea level rise projections can be integrated into different scenarios to support planning and decision-making, given uncertainty and future risks. This approach allows for the many different probabilistic projections (i.e., two models each using two greenhouse gas concentration pathways for multiple time series and several probabilities groups) to be filtered into four scenarios. Under this approach, each of the scenarios—Intermediate, Intermediate-High, High, and Extreme—is cross-walked with two or three probabilistic model outputs

On their own, while they are not site-specific projections of mean higher high water levels, these projections provide insight to overall trends in rising sea levels along the Commonwealth coastline, to help coastal municipal officials and workshop participants identify future hazards exacerbated by rising seas.

(For definitions of scenarios and projections shown in this map please reference the section on sea level rise beginning on page 11 of this 2018 report.)

*Please Note that the MA temperature and precipitation projections in this 2018 report have been superseded by those sourced from Cornell University and featured in this map viewer and the Climate Projections Dashboard: Massachusetts Climate and Hydrologic Risk Project (Phase 1) – Stochastic Weather Generator Climate Projections Dataset

IntroductionClimate Central’s Surging Seas: Risk Zone map shows areas vulnerable to near-term flooding from different combinations of sea level rise, storm surge, tides, and tsunamis, or to permanent submersion by long-term sea level rise. Within the U.S., it incorporates the latest, high-resolution, high-accuracy lidar elevation data supplied by NOAA (exceptions: see Sources), displays points of interest, and contains layers displaying social vulnerability, population density, and property value. Outside the U.S., it utilizes satellite-based elevation data from NASA in some locations, and Climate Central’s more accurate CoastalDEM in others (see Methods and Qualifiers). It provides the ability to search by location name or postal code.The accompanying Risk Finder is an interactive data toolkit available for some countries that provides local projections and assessments of exposure to sea level rise and coastal flooding tabulated for many sub-national districts, down to cities and postal codes in the U.S. Exposure assessments always include land and population, and in the U.S. extend to over 100 demographic, economic, infrastructure and environmental variables using data drawn mainly from federal sources, including NOAA, USGS, FEMA, DOT, DOE, DOI, EPA, FCC and the Census.This web tool was highlighted at the launch of The White House's Climate Data Initiative in March 2014. Climate Central's original Surging Seas was featured on NBC, CBS, and PBS U.S. national news, the cover of The New York Times, in hundreds of other stories, and in testimony for the U.S. Senate. The Atlantic Cities named it the most important map of 2012. Both the Risk Zone map and the Risk Finder are grounded in peer-reviewed science.Back to topMethods and QualifiersThis map is based on analysis of digital elevation models mosaicked together for near-total coverage of the global coast. Details and sources for U.S. and international data are below. Elevations are transformed so they are expressed relative to local high tide lines (Mean Higher High Water, or MHHW). A simple elevation threshold-based “bathtub method” is then applied to determine areas below different water levels, relative to MHHW. Within the U.S., areas below the selected water level but apparently not connected to the ocean at that level are shown in a stippled green (as opposed to solid blue) on the map. Outside the U.S., due to data quality issues and data limitations, all areas below the selected level are shown as solid blue, unless separated from the ocean by a ridge at least 20 meters (66 feet) above MHHW, in which case they are shown as not affected (no blue).Areas using lidar-based elevation data: U.S. coastal states except AlaskaElevation data used for parts of this map within the U.S. come almost entirely from ~5-meter horizontal resolution digital elevation models curated and distributed by NOAA in its Coastal Lidar collection, derived from high-accuracy laser-rangefinding measurements. The same data are used in NOAA’s Sea Level Rise Viewer. (High-resolution elevation data for Louisiana, southeast Virginia, and limited other areas comes from the U.S. Geological Survey (USGS)). Areas using CoastalDEM™ elevation data: Antigua and Barbuda, Barbados, Corn Island (Nicaragua), Dominica, Dominican Republic, Grenada, Guyana, Haiti, Jamaica, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, San Blas (Panama), Suriname, The Bahamas, Trinidad and Tobago. CoastalDEM™ is a proprietary high-accuracy bare earth elevation dataset developed especially for low-lying coastal areas by Climate Central. Use our contact form to request more information.Warning for areas using other elevation data (all other areas)Areas of this map not listed above use elevation data on a roughly 90-meter horizontal resolution grid derived from NASA’s Shuttle Radar Topography Mission (SRTM). SRTM provides surface elevations, not bare earth elevations, causing it to commonly overestimate elevations, especially in areas with dense and tall buildings or vegetation. Therefore, the map under-portrays areas that could be submerged at each water level, and exposure is greater than shown (Kulp and Strauss, 2016). However, SRTM includes error in both directions, so some areas showing exposure may not be at risk.SRTM data do not cover latitudes farther north than 60 degrees or farther south than 56 degrees, meaning that sparsely populated parts of Arctic Circle nations are not mapped here, and may show visual artifacts.Areas of this map in Alaska use elevation data on a roughly 60-meter horizontal resolution grid supplied by the U.S. Geological Survey (USGS). This data is referenced to a vertical reference frame from 1929, based on historic sea levels, and with no established conversion to modern reference frames. The data also do not take into account subsequent land uplift and subsidence, widespread in the state. As a consequence, low confidence should be placed in Alaska map portions.Flood control structures (U.S.)Levees, walls, dams or other features may protect some areas, especially at lower elevations. Levees and other flood control structures are included in this map within but not outside of the U.S., due to poor and missing data. Within the U.S., data limitations, such as an incomplete inventory of levees, and a lack of levee height data, still make assessing protection difficult. For this map, levees are assumed high and strong enough for flood protection. However, it is important to note that only 8% of monitored levees in the U.S. are rated in “Acceptable” condition (ASCE). Also note that the map implicitly includes unmapped levees and their heights, if broad enough to be effectively captured directly by the elevation data.For more information on how Surging Seas incorporates levees and elevation data in Louisiana, view our Louisiana levees and DEMs methods PDF. For more information on how Surging Seas incorporates dams in Massachusetts, view the Surging Seas column of the web tools comparison matrix for Massachusetts.ErrorErrors or omissions in elevation or levee data may lead to areas being misclassified. Furthermore, this analysis does not account for future erosion, marsh migration, or construction. As is general best practice, local detail should be verified with a site visit. Sites located in zones below a given water level may or may not be subject to flooding at that level, and sites shown as isolated may or may not be be so. Areas may be connected to water via porous bedrock geology, and also may also be connected via channels, holes, or passages for drainage that the elevation data fails to or cannot pick up. In addition, sea level rise may cause problems even in isolated low zones during rainstorms by inhibiting drainage.ConnectivityAt any water height, there will be isolated, low-lying areas whose elevation falls below the water level, but are protected from coastal flooding by either man-made flood control structures (such as levees), or the natural topography of the surrounding land. In areas using lidar-based elevation data or CoastalDEM (see above), elevation data is accurate enough that non-connected areas can be clearly identified and treated separately in analysis (these areas are colored green on the map). In the U.S., levee data are complete enough to factor levees into determining connectivity as well.However, in other areas, elevation data is much less accurate, and noisy error often produces “speckled” artifacts in the flood maps, commonly in areas that should show complete inundation. Removing non-connected areas in these places could greatly underestimate the potential for flood exposure. For this reason, in these regions, the only areas removed from the map and excluded from analysis are separated from the ocean by a ridge of at least 20 meters (66 feet) above the local high tide line, according to the data, so coastal flooding would almost certainly be impossible (e.g., the Caspian Sea region).Back to topData LayersWater Level | Projections | Legend | Social Vulnerability | Population | Ethnicity | Income | Property | LandmarksWater LevelWater level means feet or meters above the local high tide line (“Mean Higher High Water”) instead of standard elevation. Methods described above explain how each map is generated based on a selected water level. Water can reach different levels in different time frames through combinations of sea level rise, tide and storm surge. Tide gauges shown on the map show related projections (see just below).The highest water levels on this map (10, 20 and 30 meters) provide reference points for possible flood risk from tsunamis, in regions prone to them.

These data were created as part of the National Oceanic and Atmospheric Administration Office for Coastal Management's efforts to create an online mapping viewer called the Sea Level Rise and Coastal Flooding Impacts Viewer. It depicts potential sea level rise and its associated impacts on the nation's coastal areas. The purpose of the mapping viewer is to provide coastal managers and scientists with a preliminary look at sea level rise and coastal flooding impacts. The viewer is a screening-level tool that uses nationally consistent data sets and analyses. Data and maps provided can be used at several scales to help gauge trends and prioritize actions for different scenarios. The Sea Level Rise and Coastal Flooding Impacts Viewer may be accessed at: https://coast.noaa.gov/slr. This metadata record describes the Massachusetts digital elevation model (DEM), which is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Office for Coastal Management's Sea Level Rise and Coastal Flooding Impacts Viewer described above. This DEM includes the best available lidar known to exist at the time of DEM creation that met project specifications. This DEM includes data for Barnstable, Bristol, Dukes, Essex, Middlesex, Nantucket, Plymouth, Suffolk, and Norfolk Counties. The DEM was produced from the following lidar data sets: 1. 2013 - 2014 USGS Hurricane Sandy Supplemental for NE (RI, MA, NH) 2. 2011 USGS ARRA Lidar for the Northeast: Massachusetts The DEM is referenced vertically to the North American Vertical Datum of 1988 (NAVD88, Geoid12B) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). The resolution of the DEM is approximately 3 meters.

These data were created as part of the National Oceanic and Atmospheric Administration Office for Coastal Management's efforts to create an online mapping viewer called the Sea Level Rise and Coastal Flooding Impacts Viewer. It depicts potential sea level rise and its associated impacts on the nation's coastal areas. The purpose of the mapping viewer is to provide coastal managers and scientists with a preliminary look at sea level rise (slr) and coastal flooding impacts. The viewer is a screening-level tool that uses nationally consistent data sets and analyses. Data and maps provided can be used at several scales to help gauge trends and prioritize actions for different scenarios. The Sea Level Rise and Coastal Flooding Impacts Viewer may be accessed at: http://www.coast.noaa.gov/slr This metadata record describes the Boston Weather Forecast Office (BOX WFO) digital elevation model (DEM), which is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Office for Coastal Management's Sea Level Rise and Coastal Flooding Impacts Viewer described above. The DEMs created for this project were developed using the NOAA National Weather Service's Weather Forecast Office (WFO) boundaries. The DEM includes the best available lidar known to exist at the time of DEM creation that met project specifications for the Boston WFO, which includes the coastal counties of Massachusetts and Rhode Island. The DEM was produced from LiDAR datasets acquired by the U.S. Geological Survey (USGS) under the LiDAR for the Northeast Project along with LiDAR datasets for Dukes County, Nantucket, and the City of Boston. Hydrographic breaklines were delineated from LiDAR intensity imagery generated from the LiDAR datasets. The final DEM is hydro flattened such that water elevations are less than or equal to -0.5 meters. The DEM is referenced vertically to the North American Vertical Datum of 1988 (NAVD88) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). The resolution of the DEM is approximately 5 meters.

The coastal vulnerability index (CVI)provides a preliminary overview, at a National scale, of the relative susceptibility of the Nation's coast to sea-level rise. This initial classification is based upon variables including geomorphology, regional coastal slope, tide range, wave height, relative sea-level rise, and shoreline erosion and accretion rates. The combination of these variables and the association of these variables to each other furnish a broad overview of coastal regions where physical changes are likely to occur due to sea-level rise.

To make this coastal vulnerability index data more accessible to the public and other agencies, the USGS created this web service. This web service was created utilizing ESRI ArcServer. Vector layers were collected, organized by the coastal regions of the U.S., U.S. Atlantic, Pacific and Gulf of Mexico Coasts, and symbology made consistent among similar data sets. This service meets open geospatial consortium standards.

The geographic information system (GIS) data layers from this web service are cataloged by region for ease of access.

In 1980, Executive Order No. 181 was enacted to strengthen the protection of barrier beaches in Massachusetts. This order recognized that: the dynamic nature of the barrier is essential for barrier beaches to provide storm damage prevention and flood control; human-induced changes to barrier beaches can decrease these storm damage prevention and flood control capacities; inappropriate development on barrier beaches results in the loss of lives and property; and future storm damage to development on barrier beaches is inevitable due to sea level rise.In recognition of these factors, the Executive Order discourages further development on barrier beaches by limiting state and federal funding for new support facilities, such as sewer and water lines and coastal engineering structures; clarifies state wetland policy for managing the natural characteristics of these areas; gives priority status for relocation assistance to storm damaged barrier beach areas; and encourages public acquisition of barrier beaches for recreational purposes.To implement Executive Order No. 181, the Massachusetts Office of Coastal Zone Management (CZM) undertook the Massachusetts Barrier Beach Inventory Project. In 1982, CZM completed this comprehensive effort to identify and delineate the 681 barrier beaches in Massachusetts and to place them on topographic maps.In 2007, CZM made them available through the Massachusetts Ocean Resource Information System (MORIS), a web-based coastal mapping tool. A more up-to-date inventory of barrier beaches identified through remote sensing is available on the Massachusetts Department of Environmental Protection (MassDEP) detailed wetlands GIS layer (1:12,000), also available on MORIS. Although a variety of data was collected to support the mapping of Massachusetts barrier beaches, detailed subsurface geological information was not available for each individual coastal barrier. Therefore, it is possible that some landforms, or portions thereof, that have been identified as barriers should not have been. Conversely, there may be landforms that are barriers but were not so identified.Excerpted from CZM's Massachusetts Barrier Beach Inventory webpage.

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Cape Cod National Seashore in Massachusetts. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range and mean significant wave height. The rankings for each input variable were combined and an index value calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI and the data contained within this dataset provide an objective technique for evaluation and long-term planning by scientists and park managers.

This data set describes sea floor characteristics for the Western Massachusetts Bay. This data set was created using sidescan-sonar imagery, photography, and sediment samples.

This item is the root of the tree that represents the navigable items or 'enabled' items. Adding aggregations or data items to this will display them as top-level items on the portal home. This item is not displayed on the portal, so none of these fields need ever be edited.

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Gulf Islands National Seashore in Mississippi and Florida. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range and mean significant wave height. The rankings for each input variable were combined and an index value calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI and the data contained within this dataset provide an objective technique for evaluation and long-term planning by scientists and park managers.

Accurate data and maps of sea floor geology are important first steps toward protecting fish habitat, delineating marine resources, and assessing environmental changes due to natural or human impacts. To address these concerns the U.S. Geological Survey, in cooperation with the Massachusetts Office of Coastal Zone Management (CZM), comprehensively mapped the Cape Cod Bay sea floor to characterize the surface and shallow subsurface geologic framework. Geophysical data collected include swath bathymetry, backscatter, and seismic reflection profile data. Ground-truth data, including sediment samples, underwater video, and bottom photographs were also collected. This effort is part of a long-term collaboration between the USGS and the Commonwealth of Massachusetts to map the State’s waters, support research on the Quaternary evolution of coastal Massachusetts, the influence of sea-level change and sediment supply on coastal evolution, and efforts to understand the type, distribution, ...

Accurate data and maps of sea floor geology are important first steps toward protecting fish habitat, delineating marine resources, and assessing environmental changes due to natural or human impacts. To address these concerns the U.S. Geological Survey, in cooperation with the Massachusetts Office of Coastal Zone Management (CZM), comprehensively mapped the Cape Cod Bay sea floor to characterize the surface and shallow subsurface geologic framework. Geophysical data collected include swath bathymetry, backscatter, and seismic reflection profile data. Ground-truth data, including sediment samples, underwater video, and bottom photographs were also collected. This effort is part of a long-term collaboration between the USGS and the Commonwealth of Massachusetts to map the State's waters, support research on the Quaternary evolution of coastal Massachusetts, the influence of sea-level change and sediment supply on coastal evolution, and efforts to understand the type, distribution, and quality of subtidal marine habitats. This collaboration produces high-resolution geologic maps and Geographic Information System (GIS) data that serve the needs of research, management and the public. Data collected as part of this mapping cooperative continue to be released in a series of USGS Open-File Reports and Data Releases (https://www.usgs.gov/centers/whcmsc/science/geologic-mapping-massachusetts-seafloor). This data release provides the geophysical and geologic sampling data collected in Cape Cod Bay during USGS Field Activities 2019-002-FA and 2019-034-FA in 2019.

A bare earth elevation and bathymetry DEM to be used for sea level rise modeling and general visualization. All elevation and bathymetry inputs were converted to a common horizontal and vertical coordinate systems prior to processing. All points were input into and ArcGIS Terrain dataset for triangular linear interpolation and creation of the final 1m resolution DEM. If conversion was required for the vertical coordinate system, common with sounding points referenced to Mean Low Water (MLW) or Mean Lower-Low Water (MLLW), the NOAA vertical datum transformation tool (VDatum) (https://vdatum.noaa.gov/) was used to transform the values from a tidal datum to a geodetic datum.Horizontal Coordinate System: UTM 19N NAD83, units meters (EPSG:26919)Vertical Coordinate System: NAVD88, units meters, positive up (EPSG:5703)Cell spacing: 1 meterInput Datasets:TOPOGRAPHY2021 USGS Lidar: Central Eastern MassachusettsThe Central Eastern Massachusetts Lidar project called for the planning, acquisition, and processing of lidar data collected to Quality Level 1 (QL1) standards. Project specifications are based on the U.S. Geological Survey National Geospatial Program LIDAR Base Specification 2020 Revision A. The data was developed based on the NAD83(2011) horizontal datum and the NAVD88 Geoid 18 vertical datum.Short Citation: OCM Partners, 2025: 2021 USGS Lidar: Central Eastern Massachusetts, https://www.fisheries.noaa.gov/inport/item/69417. BATHYMETRY2015 NOAA NGS Topobathy Lidar: Buzzards Bay Block2 (MA)These data were collected by the National Oceanic Atmospheric Administration National Geodetic Survey Remote Sensing Division using a Riegl VQ820G system. The data were acquired from 20151104 - 20151109. The data includes topobathy data in an LAS 1.2 format file classified as unclassified (1), ground (2), noise (7), bathymetric point (24), sensor noise refracted (26), topobathy water surface (27), and International Hydrographic Organization (IHO) S-57 object (30) in accordance with the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards.Short Citation: National Geodetic Survey, 2025: 2015 NOAA NGS Topobathy Lidar: Buzzards Bay Block2 (MA), https://www.fisheries.noaa.gov/inport/item/48191. Continuously Updated Digital Elevation Model (CUDEM) - 1/9 Arc-Second Resolution Bathymetric-Topographic TilesNOAA's National Centers for Environmental Information (NCEI) is developing a suite of digital elevation models (DEMs) for the U.S. coast to support a variety of NOAA missions, including improved inundation modeling and mapping, habitat characterization, and visualization of Earth's surface. The DEMs are being developed according to a 0.25 degree tiling scheme. The spatial resolution of the tiles "telescopes" from the coastal zone to the deep ocean floor at 1/9, 1/3, and 3 arc-second grid resolution. Only the 1/9 arc-second DEM tiles integrate both bathymetric and topographic data; all other resolutions map bathymetry only. The tiling of the DEMs facilitates targeted, rapid updates as new coastal and marine elevation data are acquired and become available.Citation: Amante, C.J.; Love, M.; Carignan, K.; Sutherland, M.G.; MacFerrin, M.; Lim, E. Continuously Updated Digital Elevation Models (CUDEMs) to Support Coastal Inundation Modeling. Remote Sens. 2023, 15, 1702. https://doi.org/10.3390/rs15061702 2024 US Army Corps of Engineers District: CENAE, New Bedford Harbor Condition Survey

Accurate data and maps of sea floor geology are important first steps toward protecting fish habitat, delineating marine resources, and assessing environmental changes due to natural or human impacts. To address these concerns the U.S. Geological Survey, in cooperation with the Massachusetts Office of Coastal Zone Management (CZM), comprehensively mapped the Cape Cod Bay sea floor to characterize the surface and shallow subsurface geologic framework. Geophysical data collected include swath bathymetry, backscatter, and seismic reflection profile data. Ground-truth data, including sediment samples, underwater video, and bottom photographs were also collected. This effort is part of a long-term collaboration between the USGS and the Commonwealth of Massachusetts to map the State’s waters, support research on the Quaternary evolution of coastal Massachusetts, the influence of sea-level change and sediment supply on coastal evolution, and efforts to understand the type, distribution, and quality of subtidal marine habitats. This collaboration produces high-resolution geologic maps and Geographic Information System (GIS) data that serve the needs of research, management and the public. Data collected as part of this mapping cooperative continue to be released in a series of USGS Open-File Reports and Data Releases (https://www.usgs.gov/centers/whcmsc/science/geologic-mapping-massachusetts-seafloor). This data release provides the geophysical and geologic sampling data collected in Cape Cod Bay during USGS Field Activities 2019-002-FA and 2019-034-FA in 2019.