60 datasets found
  1. a

    FEMA National Flood Hazard Layer (NFHL)

    • hub.arcgis.com
    • data.cityofrochester.gov
    Updated Oct 10, 2024
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    Open_Data_Admin (2024). FEMA National Flood Hazard Layer (NFHL) [Dataset]. https://hub.arcgis.com/datasets/RochesterNY::profile-baselines-1
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    Dataset updated
    Oct 10, 2024
    Dataset authored and provided by
    Open_Data_Admin
    Area covered
    Description

    FEMA provides access to the National Flood Hazards Layer (NFHL) through web mapping services. The maps depict effective flood hazard information and supporting data. The primary flood hazard classification is indicated in the Flood Hazard Zones layer.The NFHL layers include:Flood hazard zones and labelsRiver Miles MarkersCross-sections and coastal transects and their labelsLetter of Map Revision (LOMR) boundaries and case numbersFlood Insurance Rate Map (FIRM) boundaries, labels and effective datesCoastal Barrier Resources System (CBRS) and Otherwise Protected Area (OPA) unitsCommunity boundaries and namesLeveesHydraulic and flood control structuresProfile and coastal transect baselinesLimit of Moderate Wave Action(LiMWA)Not all effective Flood Insurance Rate Maps (FIRM) have GIS data available. To view a list of available county and single-jurisdiction flood study data in GIS format and check the status of the NFHL GIS services, please visit the NFHL Status Page.Preliminary & Pending National Flood Hazard LayersThe Preliminary and Pending NFHL dataset represents the current pre-effective flood data for the country. These layers are updated as new preliminary and pending data becomes available, and data is removed from these layers as it becomes effective.For more information, please visit FEMA's website.To download map panels or GIS Data, go to: NFHL on FEMA GeoPlatform.Preliminary & Pending DataPreliminary data are for review and guidance purposes only. By viewing preliminary data and maps, the user acknowledges that the information provided is preliminary and subject to change. Preliminary data are not final and are presented in this national layer as the best information available at this time. Additionally, preliminary data cannot be used to rate flood insurance policies or enforce the Federal mandatory purchase requirement. FEMA will remove preliminary data once pending data are available.Pending data are for early awareness of upcoming changes to regulatory flood map information. Until the data becomes effective, when it will appear in FEMA's National Flood Hazard Layer (NFHL), the data should not be used to rate flood insurance policies or enforce the Federal mandatory purchase requirement. FEMA will remove pending data once effective data are available.To better understand Preliminary data please see the View Your Community's Preliminary Flood Hazard Data webpage.FEMA GeoPlatformFEMA's GIS flood map services are available through FEMAs GeoPlatform, an ArcGIS Online portal containing a variety of FEMA-related data.To view the NFHL on the FEMA GeoPlatform go to NFHL on FEMA GeoPlatform.To view the Preliminary and Pending national layers on the FEMA Geoplatform go to FEMA's Preliminary & Pending National Flood Hazard Layer.Technical InformationFlood hazard and supporting data are developed using specifications for horizontal control consistent with 1:12,000–scale mapping. If you plan to display maps from the NFHL with other map data for official purposes, ensure that the other information meets FEMA’s standards for map accuracy.The minimum horizontal positional accuracy for base map hydrographic and transportation features used with the NFHL is the NSSDA radial accuracy of 38 feet. United States Geological Survey (USGS) imagery and map services that meet this standard can be found by visiting the Knowledge Sharing Site (KSS) for Base Map Standards (420). Other base map standards can be found at https://riskmapportal.msc.fema.gov/kss/MapChanges/default.aspx. You will need a username and password to access this information.The NFHL data are from FEMA’s FIRM databases. New data are added continually. The NFHL also contains map changes to FIRM data made by LOMRs.The NFHL is stored in North American Datum of 1983, Geodetic Reference System 80 coordinate system, though many of the NFHL GIS web services support the Web Mercator Sphere projection commonly used in web mapping applications.Organization & DisplayThe NFHL is organized into many data layers. The layers display information at map scales appropriate for the data. A layer indicating the availability of NFHL data is displayed at map scales smaller than 1:250,000, regional overviews at map scales between 1:250,000 and 1:50,000, and detailed flood hazard maps at map scales of 1:50,000 and larger. The "Scalehint" item in the Capabilities file for the Web Map Service encodes the scale range for a layer.In addition, there are non-NFHL datasets provided in the GIS web services, such as information about the availability of flood data and maps, the national map panel scheme, and point locations for LOMA and LOMR-Fs. The LOMA are positioned less accurately than are the NFHL data.Layers in the public NFHL GIS services:Use the numbers shown below when referencing layers by number.0. NFHL Availability1. LOMRs2. LOMAs3. FIRM Panels4. Base Index5. PLSS6. Toplogical Low Confidence Areas7. River Mile Markers8. Datum Conversion Points9. Coastal Gages10. Gages11. Nodes12. High Water Marks13. Station Start Points14. Cross-Sections15. Coastal Transects16. Base Flood Elevations17. Profile Baselines18. Transect Baselines19. Limit of Moderate Wave Action20. Water Lines21. Coastal Barrier Resources System Area22. Political Jurisdictions23. Levees24. General Structures25. Primary Frontal Dunes26. Hydrologic Reaches27. Flood Hazard Boundaries28. Flood Hazard Zones29. Submittal Information30. Alluvial Fans31. Subbasins32. Water Areas

  2. a

    North Carolina Flood Hazard Lines - Prelim

    • nc-risk-management-open-data-ncem-gis.hub.arcgis.com
    • nconemap.gov
    • +3more
    Updated Dec 9, 2019
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    State of North Carolina - Emergency Management (2019). North Carolina Flood Hazard Lines - Prelim [Dataset]. https://nc-risk-management-open-data-ncem-gis.hub.arcgis.com/maps/north-carolina-flood-hazard-lines-prelim
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    Dataset updated
    Dec 9, 2019
    Dataset authored and provided by
    State of North Carolina - Emergency Management
    Area covered
    Description

    North Carolina Preliminary Flood Lines: In 2000, the Federal Emergency Management Agency (FEMA) designated North Carolina a Cooperating Technical Partner State, formalizing an agreement between FEMA and the State to modernize flood maps. This partnership resulted in creation of the North Carolina Floodplain Mapping Program (NCFMP). As a CTS, the State assumed primary ownership and responsibility of the Flood Insurance Rate Maps (FIRMs) for all North Carolina communities as part of the National Flood Insurance Program (NFIP). This project includes conducting flood hazard analyses and producing updated, Digital Flood Insurance Rate Maps (DFIRMs). Floodplain management is a process that aims to achieve reduced losses due to flooding. It takes on many forms, but is realized through a series of federal, state, and local programs and regulations, in concert with industry practice, to identify flood risk, implement methods to protect man-made development from flooding, and protect the natural and beneficial functions of floodplains. FIRMs are the primary tool for state and local governments to mitigate areas of flooding. Individual county databases can be downloaded from https://fris.nc.gov/fris.

    Flood Hazard Lines are a linear feature class representing the flood mapping boundaries defined by the engineering models for the 100 year, 500 year and floodway. The Flood Hazard Lines spatial table contains information about the flood hazard line features for the study area. These data are the linear representation of the boundaries of the flood hazard areas that are or will be depicted on the FIRM. These zones are currently in the process of local review and revision.

  3. P

    FEMA FLOOD MAP PRELIMINARY DECEMBER 31 2019

    • data.pompanobeachfl.gov
    Updated Jun 6, 2023
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    External Datasets (2023). FEMA FLOOD MAP PRELIMINARY DECEMBER 31 2019 [Dataset]. https://data.pompanobeachfl.gov/dataset/fema-flood-map-preliminary-december-31-2019
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    html, arcgis geoservices rest apiAvailable download formats
    Dataset updated
    Jun 6, 2023
    Dataset provided by
    BCGISFL
    Authors
    External Datasets
    Description

    Updated FEMA Flood Mapping for Broward County, FL. This is a preliminary assessment of updates to Flood Zones from December 2019.

  4. d

    MD iMAP: Preliminary FEMA Floodplain

    • catalog.data.gov
    • opendata.maryland.gov
    Updated May 10, 2025
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    opendata.maryland.gov (2025). MD iMAP: Preliminary FEMA Floodplain [Dataset]. https://catalog.data.gov/dataset/md-imap-preliminary-fema-floodplain
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    Dataset updated
    May 10, 2025
    Dataset provided by
    opendata.maryland.gov
    Area covered
    Maryland
    Description

    This is a MD iMAP hosted service. Find more information on http://imap.maryland.gov. The DFIRM Database presents the flood risk information depicted on a given Flood Insurance Rate Map (FIRM) in a digital format suitable for use in electronic mapping applications. The DFIRM database is a subset of the Digital Flood Insurance Study (FIS) database that serves to archive the information collected during the FIS. This map service is a composite of Effective and Preliminary floodplain data. Q3 data is used where neither Effective or Preliminary data is available for a given community. The primary risk classifications used are the 1-percent-annual-chance flood event - the 0.2-percent-annual- chance flood event - and areas of minimal flood risk. The DFIRM Database is derived from Flood Insurance Studies (FISs) - previously published Flood Insurance Rate Maps (FIRMs) - flood hazard analyses performed in support of the FISs and FIRMs - and new mapping data - where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). The specifications for the horizontal control of DFIRM data files are consistent with those required for mapping at a scale of 1:12 - 000. Last Updated: 03/2016 Map Service Link: https://mdgeodata.md.gov/imap/rest/services/Hydrology/MD_Floodplain/FeatureServer ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

  5. a

    FEMA Flood Zones

    • data-mcgov.opendata.arcgis.com
    Updated Jul 23, 2015
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    Martin County, Florida (2015). FEMA Flood Zones [Dataset]. https://data-mcgov.opendata.arcgis.com/datasets/fema-flood-zones-4
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    Dataset updated
    Jul 23, 2015
    Dataset authored and provided by
    Martin County, Florida
    Description

    Description

    In support of the National Flood Insurance Program NFIP, Federal Emergency Management Agency (FEMA) has undertaken an effort of flood hazard identification and mapping to update Flood Insurance Rate Maps (FIRMs) for MARTIN County.

    View Existing and Proposed Flood Map Information Using An Interactive Mapping Application.

    Contact Information

    Martin County Engineering Dept. CALL CENTER (772) 219-4945 Email: floodmap@martin.fl.us

    FEMA Map Assistance 1-877-FEMA-MAP or (1-877-336-2627) Email: FEMAMapSpecialist@mapmodteam.com

    Addtional Information

    View the preliminary maps now on the FEMA website

    https://hazards.fema.gov/femaportal/prelimdownload

    For general information about the preliminary flood hazard data, please visit

    https://www.fema.gov/pr eliminaryfloodhazarddata

    Martin County’s website provides details and a host of project informationAdditional Flood Zone Information

    Open

    Click Here to Open Web Map

  6. d

    Preliminary FEMA Floodplain

    • catalog.data.gov
    • opendata.maryland.gov
    Updated Aug 2, 2025
    + more versions
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    opendata.maryland.gov (2025). Preliminary FEMA Floodplain [Dataset]. https://catalog.data.gov/dataset/preliminary-fema-floodplain
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    Dataset updated
    Aug 2, 2025
    Dataset provided by
    opendata.maryland.gov
    Description

    This layer offers the anticipated floodplain boundaries however, the data shown are in the process of being reviewed and adopted by FEMA and a given community. Changes to the Preliminary boundaries may occur before official map adoption. Use this layer with caution. The effective regulatory floodplain should be used for conducting all official floodplain determinations until such time the preliminary floodplain is reviewed and adopted by FEMA and a given community. It is reasonable to assume that preliminary floodplain boundaries are more accurate than the Q3, but the Q3 may better represent the current regulatory Flood Insurance Rate Map (FIRM) when verified by using the paper FIRM. Last Updated: 8/31/2017

  7. P

    FEMA Flood Zones 2011

    • data.pompanobeachfl.gov
    • geohub-bcgis.opendata.arcgis.com
    • +1more
    Updated Aug 25, 2020
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    External Datasets (2020). FEMA Flood Zones 2011 [Dataset]. https://data.pompanobeachfl.gov/dataset/fema-flood-zones-2011
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    arcgis geoservices rest api, html, csv, geojson, zip, kmlAvailable download formats
    Dataset updated
    Aug 25, 2020
    Dataset provided by
    gdrice_BCGIS
    Authors
    External Datasets
    Description

    When compared to 1997 FEMA Flood Zones, an analysis done by Broward County of the 2011 data from the Federal Emergency Management Agency showed that nearly a third of Broward County properties were in areas requiring flood insurance and more than half would no longer need it. A new analysis has been done in 2020 to compare the 2019 new preliminary flood zones. This data set is historical and not the most up-to-date. Please search for the 2019 Flood Zones for updated flood zone information.

  8. a

    North Carolina Preliminary Flood Zones

    • data-nconemap.opendata.arcgis.com
    Updated May 7, 2019
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    The citation is currently not available for this dataset.
    Explore at:
    Dataset updated
    May 7, 2019
    Dataset authored and provided by
    State of North Carolina - Emergency Management
    Area covered
    Description

    North Carolina Preliminary Flood zones: In 2000, the Federal Emergency Management Agency (FEMA) designated North Carolina a Cooperating Technical Partner State, formalizing an agreement between FEMA and the State to modernize flood maps. This partnership resulted in creation of the North Carolina Floodplain Mapping Program (NCFMP). As a CTS, the State assumed primary ownership and responsibility of the Flood Insurance Rate Maps (FIRMs) for all North Carolina communities as part of the National Flood Insurance Program (NFIP). This project includes conducting flood hazard analyses and producing updated, Digital Flood Insurance Rate Maps (DFIRMs). Floodplain management is a process that aims to achieve reduced losses due to flooding. It takes on many forms, but is realized through a series of federal, state, and local programs and regulations, in concert with industry practice, to identify flood risk, implement methods to protect man-made development from flooding, and protect the natural and beneficial functions of floodplains. FIRMs are the primary tool for state and local governments to mitigate areas of flooding. The North Carolina Floodplain Mapping Program creates DFIRM maps to reflect the risk of flooding and distributes these to local communities for review and approval. These zones are currently in the process of local review and revision. Individual county databases can be downloaded from https://fris.nc.gov/fris.

  9. c

    MD iMAP: Effective FEMA Floodplain

    • s.cnmilf.com
    • opendata.maryland.gov
    • +2more
    Updated May 10, 2025
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    opendata.maryland.gov (2025). MD iMAP: Effective FEMA Floodplain [Dataset]. https://s.cnmilf.com/user74170196/https/catalog.data.gov/dataset/md-imap-effective-fema-floodplain
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    Dataset updated
    May 10, 2025
    Dataset provided by
    opendata.maryland.gov
    Area covered
    Maryland
    Description

    This is a MD iMAP hosted service. Find more information on http://imap.maryland.gov. The DFIRM Database presents the flood risk information depicted on a given Flood Insurance Rate Map (FIRM) in a digital format suitable for use in electronic mapping applications. The DFIRM database is a subset of the Digital Flood Insurance Study (FIS) database that serves to archive the information collected during the FIS. This map service is a composite of Effective and Preliminary floodplain data. Q3 data is used where neither Effective or Preliminary data is available for a given community. The primary risk classifications used are the 1-percent-annual-chance flood event - the 0.2-percent-annual- chance flood event - and areas of minimal flood risk. The DFIRM Database is derived from Flood Insurance Studies (FISs) - previously published Flood Insurance Rate Maps (FIRMs) - flood hazard analyses performed in support of the FISs and FIRMs - and new mapping data - where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). The specifications for the horizontal control of DFIRM data files are consistent with those required for mapping at a scale of 1:12 - 000. Last Updated: 03/2016 Map Service Link: https://mdgeodata.md.gov/imap/rest/services/Hydrology/MD_Floodplain/FeatureServer ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

  10. New Jersey Flood Risk Notification Tool Map

    • opendata.rcmrd.org
    Updated Sep 15, 2023
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    NJDEP Bureau of GIS (2023). New Jersey Flood Risk Notification Tool Map [Dataset]. https://opendata.rcmrd.org/maps/1d10eb21efd24c95884ee13abc68266b
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    Dataset updated
    Sep 15, 2023
    Dataset provided by
    New Jersey Department of Environmental Protectionhttp://www.nj.gov/dep/
    Authors
    NJDEP Bureau of GIS
    Area covered
    Description

    The New Jersey Flood Risk Notification Tool Map contains the GIS layers to determine potential flood risk for parcels in New Jersey. This map was developed for use in the New Jersey Flood Risk Notification Tool which can be viewed by clicking here.The Flood Risk Notice and property condition disclosure form requires you to disclose if the property is in the Special Flood Hazard Area (100-year or 1% annual chance floodplain) or the Moderate Flood Hazard Area (500-year or 1% annual chance floodplain). You will need to disclose all FEMA Flood Zones that overlap your property. There may be more than one, or there may be none. This includes any flood zones mapped according to preliminary maps. FEMA periodically re-assesses a community’s flood risk using updated data and modeling and mapping technology. These updated models are published as preliminary maps until they are made effective following a public comment or appeal period.The absence of flood indicators does not mean that a property is free from flood risk. Flooding can occur anywhere. The geographic extent of flood-prone areas can change due to local factors including increases in impervious surface; changes to stream flow; natural impediments; or aging, poorly maintained, or failing infrastructure. The size and extent of flood prone areas are also expanding due to climate change-related impacts like increasing rainfall intensities and sea-level rise.This tool does not provide information regarding the applicability of any NJDEP regulations. The absence of flood indicators does not mean that a property is free from flood risk. Flooding can occur anywhere. The geographic extent of flood-prone areas can change due to local factors including increases in impervious surface; changes to stream flow; natural impediments; or aging, poorly maintained, or failing infrastructure. The size and extent of flood-prone areas are expanding due to climate change-related impacts like increasing rainfall intensities and sea-level rise.

  11. FEMA Flood Zones - Dataset - DSO Data Discovery

    • ckan.tacc.utexas.edu
    Updated Mar 4, 2025
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    ckan.tacc.utexas.edu (2025). FEMA Flood Zones - Dataset - DSO Data Discovery [Dataset]. https://ckan.tacc.utexas.edu/dataset/fema-flood-zones
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    Dataset updated
    Mar 4, 2025
    Dataset provided by
    CKANhttps://ckan.org/
    Description

    This layer shows FEMA’s Flood Zones for Jefferson County, TX. The data was pulled from FEMA’s Preliminary FEMA Map Products and should be verified prior to final use. Contact Sean Murphy if you have any questions regarding this layer

  12. W

    FEMA Floodplain Depth Grid

    • opendata.winchesterva.gov
    • data.virginia.gov
    url
    Updated Sep 30, 2024
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    Virginia State Data (2024). FEMA Floodplain Depth Grid [Dataset]. https://opendata.winchesterva.gov/dataset/fema-floodplain-depth-grid
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    urlAvailable download formats
    Dataset updated
    Sep 30, 2024
    Dataset provided by
    Virginia Department of Conservation and Recreation
    Authors
    Virginia State Data
    Description

    Raster image service of FEMA floodplain depth grid found here: https://casdsis.dcr.virginia.gov/arcgis/rest/services/Floodplains

    The Federal Emergency Management Agency (FEMA) has broadened its delivery of flood hazard data to include a number of flood risk products. These flood risk products depict and describe the variability of flood risk in the vicinity of the 1% annual chance floodplains designated on the Flood Insurance Rate Maps (FIRMs). Flood Depth Grids are delivered to local officials during the Flood Risk Review Meetings as a part of the Flood Risk Database, prior to the preparation of the preliminary FIRMs. Flood Depth Grids allow local community officials to use technological and software advances to view and analyze hazards in their community from a new perspective.

  13. c

    MD iMAP: Maryland Floodplain - Preliminary FEMA Floodplain

    • s.cnmilf.com
    • opendata.maryland.gov
    • +2more
    Updated May 10, 2025
    + more versions
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    opendata.maryland.gov (2025). MD iMAP: Maryland Floodplain - Preliminary FEMA Floodplain [Dataset]. https://s.cnmilf.com/user74170196/https/catalog.data.gov/dataset/md-imap-maryland-floodplain-preliminary-fema-floodplain
    Explore at:
    Dataset updated
    May 10, 2025
    Dataset provided by
    opendata.maryland.gov
    Area covered
    Maryland
    Description

    This is a MD iMAP hosted service. Find more information at http://imap.maryland.gov. This layer offers the anticipated floodplain boundaries however - the data shown are in the process of being reviewed and adopted by FEMA and a given community. Changes to the Preliminary boundaries may occur before official map adoption. Use this layer with caution. The effective regulatory floodplain should be used for conducting all official floodplain determinations until such time the preliminary floodplain is reviewed and adopted by FEMA and a given community. It is reasonable to assume that preliminary floodplain boundaries are more accurate than the Q3 - but the Q3 may better represent the current regulatory Flood Insurance Rate Map (FIRM) when verified by using the paper FIRM. Last Updated: 03/2016Feature Service Link:https://mdgeodata.md.gov/imap/rest/services/Hydrology/MD_Floodplain/FeatureServer ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

  14. H

    FEMA - Harvey Flood Depths Grid

    • hydroshare.org
    • beta.hydroshare.org
    • +1more
    zip
    Updated May 12, 2020
    + more versions
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    Federal Emergency Management Administration (FEMA) (2020). FEMA - Harvey Flood Depths Grid [Dataset]. http://doi.org/10.4211/hs.165e2c3e335d40949dbf501c97827837
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    zip(1.3 MB)Available download formats
    Dataset updated
    May 12, 2020
    Dataset provided by
    HydroShare
    Authors
    Federal Emergency Management Administration (FEMA)
    License

    Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
    License information was derived automatically

    Description

    This resource describes a dataset of gridded depth at horizontal resolution of 3 meters, published November 15, 2017, downloaded from FEMA [1] and hosted in this archive at the University of Texas Advanced Computing Center (TACC) [2].. The raster dataset is contained within an Esri ArcGIS geodatabase. This product utilized Triangulated Irregular Network (TIN) interpolation, four quality assurance measures (identifying dips, spikes, duplication, and inaccurate/unrealistic measurements). High Water Marks were obtained from the Harris County Flood Control District (HCFCD), US Geological Survey (USGS), and other inspection data. Elevation data comprised a mosaic of 3 meter resampled elevations from 1M & 3M LiDAR, and IFSAR data. One section of the IfSAR data was found to be erroneous, and replaced with a blended 10 meter section. [This description was in correspondence January 22, 2018, from Mark English, GeoSpatial Risk Analyst, FEMA Region VIII, Mitigation Division.]

    A preliminary version of these depths dated September 10, 2017 can be viewed in a FEMA web map [3]. This web map shows a forecasted depth grid, based on National Weather Service (NWS) Advanced Hydrologic Prediction Service (AHPS) forecasted water levels.

    See FEMA's Natural Hazard Risk Assessment Program (NHRAP) ftp site [4] for additional HWM-based depth grids and inundation polygons: - Harris County AOIs and Inundation Boundaries [5] - Harris County Depth Grids [6] - Aransas, Nueces, and San Patricio Coastal Depth Grids and Boundaries [7] FEMA notes on these Modeled Preliminary Observations: o Based on observed Water Levels at stream gauges interpolated along rivers, downsampled to 5m resolution DEM o Depth grids updated with new observed peak crest as they become available o Will include High Water Mark information as it becomes available o Extents validated with remote sensing o Use for determining damage levels on specific structures

    See also FEMA's journal of mitigation planning and actions related to Harvey [8].

    References and related links: [1] FEMA_Depths_3m_v3.zip (39 gb ftp download) [https://data.femadata.com/Region8/Mitigation/Data_Share/] [2] TACC 39gb wget or ftp download [https://web.corral.tacc.utexas.edu/nfiedata/Harvey/flood_data/FEMA_Harvey_Depths_3m.gdb.zip] [3] FEMA map viewer for Hurricane Harvey resources (flood depths is bottom selection in layers list) [https://fema.maps.arcgis.com/apps/webappviewer/index.html?id=50f21538c7bf4e08b9faab430bc237c9] [4] FEMA NHRAP ftp [https://data.femadata.com/FIMA/NHRAP/Harvey/] [5] [https://data.femadata.com/FIMA/NHRAP/Harvey/Harris_AOIandBoundaries.zip] [6] [https://data.femadata.com/FIMA/NHRAP/Harvey/Harris_Mosaic_dgft.zip] [7] [https://data.femadata.com/FIMA/NHRAP/Harvey/Rockport_DG_unclipped.zip] [8] Hurricane Harvey Mitigation Portfolio - FEMA map journal [https://fema.maps.arcgis.com/apps/MapJournal/index.html?appid=70204cf2762d45409553fd9642700b7f]

  15. Flood Insurance Rate Maps and Base Flood Elevations, FIRM, DFIRM, BFE, FEMA...

    • data.wu.ac.at
    Updated Dec 14, 2017
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    NSGIC Local Govt | GIS Inventory (2017). Flood Insurance Rate Maps and Base Flood Elevations, FIRM, DFIRM, BFE, FEMA DFIRM preliminary map out now, published in 2009, Published in 2009, 1:24000 (1in=2000ft) scale, Brown County Government. [Dataset]. https://data.wu.ac.at/schema/data_gov/ZDlhYmY5OGQtODYzMC00OTY0LWE1NjgtMDQwNTc1MmM1YjE2
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    Dataset updated
    Dec 14, 2017
    Dataset provided by
    National States Geographic Information Council
    Area covered
    ea99dd654b230684fe47329e55ed814518a39bbe
    Description

    Flood Insurance Rate Maps and Base Flood Elevations, FIRM, DFIRM, BFE dataset current as of 2009. FEMA DFIRM preliminary map out now, published in 2009.

  16. Coastal Flood Hazard Composite Layer for the Coastal Flood Exposure Mapper

    • catalog.data.gov
    • datasets.ai
    • +3more
    Updated May 22, 2025
    + more versions
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    NOAA Office for Coastal Management (Point of Contact, Custodian) (2025). Coastal Flood Hazard Composite Layer for the Coastal Flood Exposure Mapper [Dataset]. https://catalog.data.gov/dataset/coastal-flood-hazard-composite-layer-for-the-coastal-flood-exposure-mapper1
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    Dataset updated
    May 22, 2025
    Dataset provided by
    National Oceanic and Atmospheric Administrationhttp://www.noaa.gov/
    Description

    This is a map service for the Coastal Flood Hazard Composite dataset. This dataset was created by combining hazard zones from the following datasets: FEMA V zones, FEMA A zones, FEMA shaded X zones, NOAA OCM Flood Frequency zones, NOAA OCM potential sea level rise inundation of 3 ft above current Mean Higher High Water (MHHW), and SLOSH MOMs for category 3 hurricanes. This dataset was created to support the National Oceanic and Atmospheric Administration Office for Coastal Management's Coastal Flood Exposure Mapper application. The purpose of the online mapping tool is to provide coastal managers, planners, and stakeholders a preliminary look at exposures to coastal flooding hazards. The Mapper 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 communities initiate resilience planning efforts. Currently the extent of this dataset covers U. S. coastal areas along the Gulf of Mexico and Atlantic coasts. This is a cached map service. Tiles have been cached down to Level ID 15 (1:18,055).

  17. P

    Broward County FEMA 2019 Proposed Flood Zones

    • data.pompanobeachfl.gov
    • geohub-bcgis.opendata.arcgis.com
    Updated Mar 9, 2020
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    External Datasets (2020). Broward County FEMA 2019 Proposed Flood Zones [Dataset]. https://data.pompanobeachfl.gov/dataset/broward-county-fema-2019-proposed-flood-zones
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    geojson, html, arcgis geoservices rest api, kml, zip, csvAvailable download formats
    Dataset updated
    Mar 9, 2020
    Dataset provided by
    cjennings_BCGIS
    Authors
    External Datasets
    Area covered
    Broward County
    Description

    The Flood Insurance Rate Map (FIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual-chance flood event, and areas of minimal flood risk. The FIRM Database is derived from Flood Insurance Studies (FISs), previously published FIRMs, flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). Additional information

    Source: FEMA
    Effective date: This data is current as of December 31, 2019
    Last update: 12/31/2019
    Update Cycle: When provided
    
  18. PRELIMINARY Digital Flood Insurance Database Submission for Pope County, AR...

    • data.wu.ac.at
    arce +2
    Updated Nov 14, 2017
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    Federal Emergency Management Agency, Department of Homeland Security (2017). PRELIMINARY Digital Flood Insurance Database Submission for Pope County, AR ,USA [Dataset]. https://data.wu.ac.at/schema/data_gov/YjUyN2Q0M2MtYmQ1My00MzIxLWEzODItYmMzY2Q2ZTE5Y2Fm
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    arce, shp, mapinfo interchange file (mif)Available download formats
    Dataset updated
    Nov 14, 2017
    Dataset provided by
    U.S. Department of Homeland Securityhttp://www.dhs.gov/
    Federal Emergency Management Agencyhttp://www.fema.gov/
    License

    U.S. Government Workshttps://www.usa.gov/government-works
    License information was derived automatically

    Area covered
    c5b279302ed710a880614af01225837f66bc9c26, United States
    Description

    The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual- chance flood event, and areas of minimal flood risk. The DFIRM Database is derived from Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA).The file is georeferenced to earth's surface using the Lambert Conformal Conic projection and the Arkansas State Plane NAD83 North Zone coordinate system. The specifications for the horizontal control of Base Map data files are consistent with those required for mapping at a scale of 1:24,000

  19. National Flood Hazard Layer (HESS)

    • data.bayareametro.gov
    Updated Dec 18, 2020
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    United States Federal Emergency Management Agency (2020). National Flood Hazard Layer (HESS) [Dataset]. https://data.bayareametro.gov/Land-People/National-Flood-Hazard-Layer-HESS-/nw9p-ap8v
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    kml, kmz, xlsx, csv, application/geo+json, xmlAvailable download formats
    Dataset updated
    Dec 18, 2020
    Dataset provided by
    Federal Emergency Management Agencyhttp://www.fema.gov/
    Authors
    United States Federal Emergency Management Agency
    Description

    National Flood Hazard Layer (NFHL) for development of the Parcel Inventory dataset for the Housing Element Site Selection (HESS) Pre-Screening Tool.

    This NFHL data incorporates all Flood Insurance Rate Map (FIRM) databases published by the Federal Emergency Management Agency (FEMA), and any Letters of Map Revision (LOMRs) that have been issued against those databases since their publication date. It is updated on a monthly basis. The FIRM Database is the digital, geospatial version of the flood hazard information shown on the published paper FIRMs.

    The FIRM Database depicts flood risk information and supporting data used to develop the risk data. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual-chance flood event, and areas of minimal flood risk. The FIRM Database is derived from Flood Insurance Studies (FISs), previously published FIRMs, flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data, where available. The FISs and FIRMs are published by FEMA.

    In addition to the identification of Special Flood Hazard Areas, the risk zones shown on the FIRMs are the basis for the establishment of premium rates for flood coverage offered through the National Flood Insurance Program. The FIRM Database presents the flood risk information depicted on the FIRM in a digital format suitable for use in electronic mapping applications. The FIRM Database serves to archive the information collected during the Flood Risk Project.

    ** This flood zone data should not be used for flood insurance purposes, but rather hazard mapping. FIRM data retrieved directly from the FEMA should be used for insurance programs.

    Source data, by county, was downloaded from https://msc.fema.gov/portal/advanceSearch.

  20. Preliminary DIGITAL FLOOD INSURANCE RATE MAP DATABASE, COOK COUNTY, ILLINOIS...

    • data.wu.ac.at
    arce
    Updated Nov 14, 2017
    + more versions
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    Federal Emergency Management Agency, Department of Homeland Security (2017). Preliminary DIGITAL FLOOD INSURANCE RATE MAP DATABASE, COOK COUNTY, ILLINOIS USA [Dataset]. https://data.wu.ac.at/schema/data_gov/NDg0NzBhNWItZjM4MS00MWEzLWE2ZDktYzZhYWE2NjI1YjJm
    Explore at:
    arceAvailable download formats
    Dataset updated
    Nov 14, 2017
    Dataset provided by
    Federal Emergency Management Agencyhttp://www.fema.gov/
    License

    U.S. Government Workshttps://www.usa.gov/government-works
    License information was derived automatically

    Area covered
    fdb6529f1c48e97f80370c7ec505dbe43d4af852
    Description

    The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual-chance flood event, and areas of minimal flood risk. The DFIRM Database is derived from Flood Insurance Studies (FISs), previously published Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). The file is georeferenced to earth's surface using the UTM projection and coordinate system. The specifications for the horizontal control of DFIRM data files are consistent with those required for mapping at a scale of 1:12,000.

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Open_Data_Admin (2024). FEMA National Flood Hazard Layer (NFHL) [Dataset]. https://hub.arcgis.com/datasets/RochesterNY::profile-baselines-1

FEMA National Flood Hazard Layer (NFHL)

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54 scholarly articles cite this dataset (View in Google Scholar)
Dataset updated
Oct 10, 2024
Dataset authored and provided by
Open_Data_Admin
Area covered
Description

FEMA provides access to the National Flood Hazards Layer (NFHL) through web mapping services. The maps depict effective flood hazard information and supporting data. The primary flood hazard classification is indicated in the Flood Hazard Zones layer.The NFHL layers include:Flood hazard zones and labelsRiver Miles MarkersCross-sections and coastal transects and their labelsLetter of Map Revision (LOMR) boundaries and case numbersFlood Insurance Rate Map (FIRM) boundaries, labels and effective datesCoastal Barrier Resources System (CBRS) and Otherwise Protected Area (OPA) unitsCommunity boundaries and namesLeveesHydraulic and flood control structuresProfile and coastal transect baselinesLimit of Moderate Wave Action(LiMWA)Not all effective Flood Insurance Rate Maps (FIRM) have GIS data available. To view a list of available county and single-jurisdiction flood study data in GIS format and check the status of the NFHL GIS services, please visit the NFHL Status Page.Preliminary & Pending National Flood Hazard LayersThe Preliminary and Pending NFHL dataset represents the current pre-effective flood data for the country. These layers are updated as new preliminary and pending data becomes available, and data is removed from these layers as it becomes effective.For more information, please visit FEMA's website.To download map panels or GIS Data, go to: NFHL on FEMA GeoPlatform.Preliminary & Pending DataPreliminary data are for review and guidance purposes only. By viewing preliminary data and maps, the user acknowledges that the information provided is preliminary and subject to change. Preliminary data are not final and are presented in this national layer as the best information available at this time. Additionally, preliminary data cannot be used to rate flood insurance policies or enforce the Federal mandatory purchase requirement. FEMA will remove preliminary data once pending data are available.Pending data are for early awareness of upcoming changes to regulatory flood map information. Until the data becomes effective, when it will appear in FEMA's National Flood Hazard Layer (NFHL), the data should not be used to rate flood insurance policies or enforce the Federal mandatory purchase requirement. FEMA will remove pending data once effective data are available.To better understand Preliminary data please see the View Your Community's Preliminary Flood Hazard Data webpage.FEMA GeoPlatformFEMA's GIS flood map services are available through FEMAs GeoPlatform, an ArcGIS Online portal containing a variety of FEMA-related data.To view the NFHL on the FEMA GeoPlatform go to NFHL on FEMA GeoPlatform.To view the Preliminary and Pending national layers on the FEMA Geoplatform go to FEMA's Preliminary & Pending National Flood Hazard Layer.Technical InformationFlood hazard and supporting data are developed using specifications for horizontal control consistent with 1:12,000–scale mapping. If you plan to display maps from the NFHL with other map data for official purposes, ensure that the other information meets FEMA’s standards for map accuracy.The minimum horizontal positional accuracy for base map hydrographic and transportation features used with the NFHL is the NSSDA radial accuracy of 38 feet. United States Geological Survey (USGS) imagery and map services that meet this standard can be found by visiting the Knowledge Sharing Site (KSS) for Base Map Standards (420). Other base map standards can be found at https://riskmapportal.msc.fema.gov/kss/MapChanges/default.aspx. You will need a username and password to access this information.The NFHL data are from FEMA’s FIRM databases. New data are added continually. The NFHL also contains map changes to FIRM data made by LOMRs.The NFHL is stored in North American Datum of 1983, Geodetic Reference System 80 coordinate system, though many of the NFHL GIS web services support the Web Mercator Sphere projection commonly used in web mapping applications.Organization & DisplayThe NFHL is organized into many data layers. The layers display information at map scales appropriate for the data. A layer indicating the availability of NFHL data is displayed at map scales smaller than 1:250,000, regional overviews at map scales between 1:250,000 and 1:50,000, and detailed flood hazard maps at map scales of 1:50,000 and larger. The "Scalehint" item in the Capabilities file for the Web Map Service encodes the scale range for a layer.In addition, there are non-NFHL datasets provided in the GIS web services, such as information about the availability of flood data and maps, the national map panel scheme, and point locations for LOMA and LOMR-Fs. The LOMA are positioned less accurately than are the NFHL data.Layers in the public NFHL GIS services:Use the numbers shown below when referencing layers by number.0. NFHL Availability1. LOMRs2. LOMAs3. FIRM Panels4. Base Index5. PLSS6. Toplogical Low Confidence Areas7. River Mile Markers8. Datum Conversion Points9. Coastal Gages10. Gages11. Nodes12. High Water Marks13. Station Start Points14. Cross-Sections15. Coastal Transects16. Base Flood Elevations17. Profile Baselines18. Transect Baselines19. Limit of Moderate Wave Action20. Water Lines21. Coastal Barrier Resources System Area22. Political Jurisdictions23. Levees24. General Structures25. Primary Frontal Dunes26. Hydrologic Reaches27. Flood Hazard Boundaries28. Flood Hazard Zones29. Submittal Information30. Alluvial Fans31. Subbasins32. Water Areas

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