The FEMA Flood Map Service Center (MSC) is the official public source for flood hazard information produced in support of the National Flood Insurance Program (NFIP). Use the MSC to find your official flood map, access a range of other flood hazard products, and take advantage of tools for better understanding flood risk.FEMA flood maps are continually updated through a variety of processes. Effective information that you download or print from this site may change or become superseded by new maps over time. For additional information, please see the Flood Hazard Mapping Updates Overview Fact Sheet

Analysis of ‘Flood Hazard Areas (Only FEMA - digitized data)’ provided by Analyst-2 (analyst-2.ai), based on source dataset retrieved from https://catalog.data.gov/dataset/b30208e9-5418-4a76-bed9-a05cc4993f2f on 27 January 2022.

--- Dataset description provided by original source is as follows ---

--- Original source retains full ownership of the source dataset ---

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.

Original GIS polygon dataset derived from FEMA Department based on collected data. The scale of the data is 1:786,633 and covers the entire county of Merced. Data is updated based on FEMA updates. Link to source: https://www.arcgis.com/home/webmap/viewer.html?url=https://services.arcgis.com/P3ePLMYs2RVChkJx/ArcGIS/rest/services/USA_Flood_Hazard_Reduced_Set_gdb/FeatureServer&source=sdFor a comprehensive set of FEMA flood layer data visit FEMA's National Flood Hazard Layer (NFHL) viewer at: https://hazards-fema.maps.arcgis.com/apps/webappviewer/index.html?id=8b0adb51996444d4879338b5529aa9cd

The Federal Emergency Management Agency (FEMA) partners with Tribal nations, States, and communities through the Risk Mapping, Assessment, and Planning (Risk MAP) program to identify flood hazards, assess flood risks, and provide accurate data to guide stakeholders in taking effective mitigation actions that result in safer and more resilient communities. This data is incorporated into flood maps, known as Flood Insurance Rate Maps (FIRMs), that support the National Flood Insurance Program (NFIP) and provide the basis for community floodplain management regulations and flood insurance requirements. Flood hazards are dynamic and can change frequently because of a variety of factors, including weather patterns, erosion, and new development. FEMA, through the Risk MAP program, works with communities to collect new or updated flood hazard data and periodically updates flood maps to reflect these changes.Source: FEMAEffective Date: 7/31/2024Update Cycle: When ProvidedFEMA Flood Map Information

Digital Q3 Flood Data are developed by scanning the existing FIRM hardcopy, vectorizing a thematic overlay of flood risks. Vector Q3 Flood Data files contain only certain features from the existing FIRM hardcopy. Q3 vector data are contained in one single countywide file, including all incorporated and unincorporated areas of a county.

 Digital Q3 Flood Data do not replace the existing FIRM hardcopy or, if one
 exists, DFIRM product. The product is designed to support planning activities,
 some Community Rating System activities, insurance marketing, and mortgage
 portfolio reviews. It does not provide base flood elevation information; thus,
 it has limited application for engineering analysis, particularly for site
 design or rating flood insurance policies for properties located within Special
 Flood Hazard Areas (SFHAs).

 Digital Q3 Flood Data are not tied to a base map, are not used to produce a new
 version of the FIRM hardcopy, and are not subjected to community review. The
 digital Q3 Flood Data are designed to provide guidance and a general proximity
 of the location of Special Flood Hazard Areas.

 The digital Q3 Flood Data product can be a valuable tool in screening property
 addresses within a Geographic Information System to determine flood risks.
 However, since the geographic processing performed to develop digital Q3 Flood
 Data may introduce differences with the FIRM hardcopy source, users must apply
 considerable care and judgment in the application of this product. For
 instance, digital Q3 Flood Data may be overlaid on highly detailed large-scale
 community base mapping data, but, if parcel level determinations are made, they
 must be prefaced with information about the accuracy of the data from which
 they are derived.

 Contents of Q3 Data

 The vectorized features contained in digital Q3 Flood Data files include:

 - Annual chance floodplain areas of 1 and 0.2 percent, including Zone V areas,
 certain floodway areas, and zone designations
 - Political areas, including community identification numbers
 - FIRM panel areas, including panel number and suffix
 - 7.5-minute quadrangle areas
 - Mapable Letters of Map Change (LOMCs)

 [Summary provided by FEMA]

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 Universal Transverse Mercator Zone 18 North. The specifications for the horizontal control of DFIRM data files are consistent with those required for mapping at a scale of 1:12,000. Coastal study data as defined in FEMA Gudelines and Specifications, Appendix D: Guidance for Coastal Flooding Analyses and Mapping, submitted as a result of a coastal study. Appendix D notes that a variety of analytical methodologies may be used to establish Base (1-percent-annual-chance) Flood Elevations (BFEs) and floodplains throughout coastal areas of the United States. Appendix D itemizes references for the methodologies currently in use by FEMA for specific coastal flood hazards, provides general guidance for documentation of a coastal flood hazard analysis, specifies flood hazard analysis procedures for the Great Lakes coasts, and outlines intermediate data submissions for coastal flood hazard analyses with new storm surge modeling and revised stillwater flood level (SWFL). (Source: FEMA Guidelines and Specs, Appendix D Guidance for Coastal Flooding Analyses and Mapping, Section D.1)

The Federal Emergency Managment Agency and the MNDNR produce Digital Flood Insurance Rate Maps (DFIRM) for selected counties in the state. These maps are often referred to as FEMA Floodplain maps.

A DFIRM is the offical digital map of a community on which FEMA has delineated the special flood hazard areas, i.e., the floodplain areas where flood insurance is required for loans and where communities will administer floodplain regulations. (Note: Communities may regulate additional flood prone areas that are not on the FIRM).

Here are some of the feature classes included in the MNDNR's publication of the DFIRM Dataset:

FEMA DFIRM Base Flood Elevations
The Base Flood Elevation (BFE) table is required for any digital data where BFE lines will be shown on the corresponding Flood Insurance Rate Map (FIRM). Normally, if there are any riverine AE zones, BFE lines are required. The BFE table contains information about the BFEs within a study area. A spatial file with locational information also corresponds with this data table. BFE lines indicate the rounded whole-foot water-surface elevation of the 1-percent-annual-chance flood. The spatial elements representing BFE features are lines extending from Special Flood Hazard Area (SFHA) boundary to SFHA boundary. The BFE lines will have no visible gaps or overshoots between the SFHA boundary and the end of the BFE line at the publication scale of the DFIRM. However, the ends of the BFE lines are not necessarily snapped precisely to the SFHA boundary. Each BFE is represented by a single line. While BFE lines are depicted as wavy lines on the hardcopy FIRM, they should be primarily straight lines in the spatial data, although they may bend consistent with procedures described in Volume 1 of these Guidelines.

FEMA DFIRM Flood Hazard Zones
FEMA flood hazard delineations are used by FEMA to designate the SFHA and for insurance rating purposes. These data are the flood hazard areas that are or will be depicted on the FIRM.

FEMA DFIRM Panel Scheme Polygons
This layer contains information about the FIRM panel areas. The spatial entities representing FIRM panels are polygons. The polygon for the FIRM panel corresponds to the panel neatlines. As a result, the panels are generally rectangular. In situations where a portion of a panel lies outside of the jurisdiction being mapped, the user must refer to the S_POL_AR table to determine the portion of the panel area where the DFIRM database shows the effective flood hazard data for the mapped jurisdiction.

FEMA DFIRM Cross Sections
FEMA Cross Sections are required for any Digital Flood Insurance Rate Map database where cross sections are shown on the FIRM. Normally any FIRM that has associated flood profiles has cross sections. The corresponding attribute table contains information about cross section lines. A spatial file with locational information also corresponds with this data table. These lines represent the locations of channel surveys performed for input into the hydraulic model used to calculate flood elevations. These locations are also shown on the Flood Profiles in the Flood Insurance Study (FIS) report and can be used to cross reference the Flood Profiles to the planimetric depiction of the flood hazards. All cross sections for which a spatial location is available should be included in this table. The spatial elements representing cross sections are lines generally extending from outside the floodplain, across the entire floodplain and out the other side. Each cross section should be represented by a single line feature without the hexagons shown on each end on the hardcopy map. The location and shape of the lines should depict as accurately as possible the position of the cross section used. This is a modified Standard DFIRM Database table that includes Standard DFIRM Database items and Enhanced Database items. All items after SOURCE_CIT are Enhanced. The Enhanced DFIRM Database must contain all modeled cross sections, whether they are printed on the FIRM or not.

Extensive information regarding the source data can be found in these two documents:
FEMA DFIRM Doc Appendix L Part A.pdf
FEMA DFIRM Doc Appendix L Part B.pdf

The FEMA Flood Map Service Center (MSC) is the official public source for flood hazard information.

This hosted feature layer has been published in RI State Plane Feet NAD 83.Statewide flood hazard areas compiled from county-based Digital Flood Insurance Rate Map (DFIRM) databases for Rhode Island. 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. TheDFIRM 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), and in this case redistributed by the Rhode Island Geographic Information System (RIGIS) at the request of the Rhode Island Emergency Management Agency.This dataset provides the user with information on the flood risk hazard zones throughout the state of Rhode Island. Note: the above summary is a slightly modified version adapted from source metadata records provided by FEMA. To provide the user with information on the statewide flood risk based on information provided by the Federal Emergency Management Agency (FEMA) in the DFIRM databases created specifically for the five counties of Rhode Island (Bristol, Kent, Newport, Providence, and Washington). This dataset provides information on the likelihood that a flood may occur at a given location in the state. The files and information used to create this dataset were originally provided to the Rhode Island Emergency Management Agency (RIEMA) by FEMA.This information was in the form of DFIRM databases for each of the five RI counties. This information was then redistributed by RIGIS at the request of RIEMA. The information provided by this data is only a subset of the information available in the original DFIRM databases located on the RIGIS website. For a specific county's complete DFIRM database, please visit the RIGIS website and download the appropriate DFIRM database. This metadata record is specific to this dataset and only contains information relevant to this dataset as provided by FEMA the original DFIRM metadata records. These can be found and referenced in the /DOCUMENT folder that is downloaded as part of a DFIRM package for a specific Rhode Island county. Another valuable source of documentation is FEMA's "Guidelines and Specifications for Flood Hazard Mapping Partners". It is currently available online at https://www.fema.gov/guidelines-and-standards-flood-risk-analysis-and-mapping. The Guide offers a tremendous amount of information regarding how DFIRM data are created, and detailed information about the individual files that constitute a DFIRM database.

Elevation data, as defined in FEMA's Guidelines and Standards for Flood Risk Analysis and Mapping, describe the digital topographic data that were used to create the data representing the terrain environment of a watershed and/or floodplain. Elevation data requirements allow for flexibility in the types of information used to produce final levation deliverables. Submission of the terrain data sources allows FEMA to account for the origins of the flood study terrain data. (Source: FEMA Guidelines and Standards for Flood Risk Analysis and Mapping.)

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 Delaware (FIPS 0700) State Plane 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. Coastal study data as defined in FEMA Gudelines and Specifications, Appendix D: Guidance for Coastal Flooding Analyses and Mapping, submitted as a result of a coastal study. Appendix D notes that a variety of analytical methodologies may be used to establish Base (1-percent-annual-chance) Flood Elevations (BFEs) and floodplains throughout coastal areas of the United States. Appendix D itemizes references for the methodologies currently in use by FEMA for specific coastal flood hazards, provides general guidance for documentation of a coastal flood hazard analysis, specifies flood hazard analysis procedures for the Great Lakes coasts, and outlines intermediate data submissions for coastal flood hazard analyses with new storm surge modeling and revised stillwater flood level (SWFL). (Source: FEMA Guidelines and Specs, Appendix D Guidance for Coastal Flooding Analyses and Mapping, Section D.1)

Analysis of ‘2013 FEMA Water Area’ provided by Analyst-2 (analyst-2.ai), based on source dataset retrieved from https://catalog.data.gov/dataset/3ea10e7b-0cc7-40ee-9a8c-b0219b42cba1 on 26 January 2022.

--- Dataset description provided by original source is as follows ---

The National Flood Hazard Layer (NFHL) data incorporates all Digital Flood Insurance Rate Map(DFIRM) databases published by FEMA, and any Letters Of Map Revision (LOMRs) that have been issued against those databases since their publication date. The DFIRM Database is the digital, geospatial version of the flood hazard information shown on the published paper Flood Insurance Rate Maps(FIRMs). 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 NFHL data are 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 are consistent with those required for mapping at a scale of 1:12,000. The NFHL data contain layers in the Standard DFIRM datasets except for S_Label_Pt and S_Label_Ld. The NFHL is available as State or US Territory data sets. Each State or Territory data set consists of all DFIRMs and corresponding LOMRs available on the publication date of the data set.

--- Original source retains full ownership of the source dataset ---

Analysis of ‘DFIRM Floodways’ provided by Analyst-2 (analyst-2.ai), based on source dataset retrieved from https://catalog.data.gov/dataset/6aafff86-f27a-459d-bc5c-b30e52f36260 on 27 January 2022.

--- Dataset description provided by original source is as follows ---

--- Original source retains full ownership of the source dataset ---

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

FEMA flood hazard areas for Metro Nashville and Davidson County.Source Link: https://www.fema.gov/flood-mapsMetadata Document: FEMA Flood Hazard Areas Metadata.pdfContact Data Owner: opendata@nashville.gov

This layer was developed by the Research & Analytics Division of the Atlanta Regional Commission and represents the 100-year and 500-year floodplain data as delineated on Flood Insurance Rate Maps (FIRMs) published by FEMA. Features captured from the paper FIRMs include floodplain boundaries, political boundaries, FIRM panel areas, and USGS 7.5-minute quadrangle boundaries. Potential applications of this "Q3" flood data include floodplain management, hazards analysis and risk assessment. In addition, the risk zones serve to establish premium rates for flood insurance offered through the National Flood Insurance Program. For more information, go to https://msc.fema.gov.Attributes:FIPS Standard 5-digit State and County FIPS codes. Definition source is from Federal Information Processing Standard (FIPS), National Institute of Standards & Technology (NIST); first 2 digits for state, last 3 digits for county.COMMUNITY Identifies a county, city, or other community responsible for flood plain management. Numeric value assigned by FEMA,(0..9999).FIRM_PANEL Eleven-digit alpha-numeric code identifies portion of community covered or not covered by a FIRM panel. Code comprises a unique alpha-numeric sequence based on FIPS and FEMA Community and Panel identification.QUAD USGS 7.5-minute quadrangle identifier.ZONE Flood hazard zone designation. Multiple Codes refer to "Q3 Flood Data Specifications" VALUES DESCRIPTION V An area inundated by 100-year flooding with velocity hazard (wave action); no Base Flood Elevation (BFEs) have been determined. VE An area inundated by 100-year flooding with velocity hazard (wave action); BFEs have been determined. A An area inundated by 100-year flooding, for which no BFEs have been determined. AE An area inundated by 100-year flooding, for which BFEs have been determined. AO An area inundated by 100-year flooding (usually sheet flow on sloping terrain), for which average depths have been determined; flood depths range from 1 to 3 feet. AOVEL An alluvial fan inundated by 100-year flooding (usually sheet flow on sloping terrain), for which average flood depths and velocities have been determined; flood depths range from 1 to 3 feet. AH An area inundated by 100-year flooding (usually an area of ponding), for which BFEs have been determined; flood depths range from 1 to 3 feet. A99 An area inundated by 100-year flooding, for which no BFEs have been determined. This is an area to be protected from the 100-year flood by a Federal flood protection system under construction. D An area of undetermined but possible flood hazards. AR An area inundated by flooding, for which BFEs or average depths have been determined. This is an area that was previously, and will again, be protected from the 100-year flood by a Federal flood protection system whose restoration is Federally funded and underway. X500 An area inundated by 500-year flooding; an area inundated by 100-year flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; or an area protected by levees from the 100-year flooding. X An area that is determined to be outside the 100- and 500-year floodplains. 100IC An area where the 100-year flooding is contained within the channel banks and the channel is too narrow to show to scale. An arbitrary channel width of 3 meters is shown. BFEs are not shown in this area, although they may be reflected on the corresponding profile. 500IC An area where the 500-year flooding is contained within the channel banks and the channel is too narrow to show to scale. An arbitrary channel width of 3 meters is shown. FWIC An area where the floodway is contained within the channel banks and the channel is too narrow to show to scale. An arbitrary channel width of 3 meters is shown. BFEs are not shown in this area, although they may be reflected on the corresponding profile. FPQ An area designated as a "Flood Prone Area" on a map prepared by USGS and the Federal Insurance Administration. This area has been delineated based on available information on past floods. This is an area inundated by 100-year flooding for which no BFEs have been determined.FLOODWAY Channel, river or watercourse reserved for flood discharge. Multiple Codes refer to "Q3 Flood Data Specifications".COBRA Undeveloped Coastal Barrier Area. Multiple Codes refer to "Q3 Flood Data Specifications".SFHA In/Out of flood zone designation, determined from data topology. VALUES DESCRIPTION IN An area designated as within a "Special Flood Hazard Area" (or SFHA) on a FIRM. This is an area inundated by 100-year flooding for which no BFEs or velocity may have been determined. No distinctions are made between the different flood hazard zones that may be included within the SFHA. These may include Zones A, AE, AO, AH, A99, AR, V, or VE. OUT An area designated as outside a "Special Flood Hazard Area" (or SFHA) on a FIRM. This is an area inundated by 500-year flooding; an area inundated by 100-year flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; an area protected by levees from 100-year flooding; or an area that is determined to be outside the 100- and 500-year floodplains. No distinctions are made between these different conditions. These may include both shaded and unshaded areas of Zone X. ANI An area that is located within a community or county that is not mapped on any published FIRM. UNDES A body of open water, such as a pond, lake ocean, etc., located within a community's jurisdictional limits, that has no defined flood hazard.SYMBOL Polygon shade symbols for graphic output, based on polygon codes. Multiple Codes refer to "Q3 Flood Data Specifications"PANEL_TYP Type of FIRM panel represented. Multiple Codes refer to "Q3 Flood Data Specifications".ST_FIPS State FIPS codeCO_FIPS County FIPS codeSource: Federal Emergency Management Agency (FEMA), Atlanta Regional CommissionDate: 1998

Elevation data, as defined in FEMA's Guidelines and Standards for Flood Risk Analysis and Mapping, describe the digital topographic data that were used to create the data representing the terrain environment of a watershed and/or floodplain. Elevation data requirements allow for flexibility in the types of information used to produce final levation deliverables. Submission of the terrain data sources allows FEMA to account for the origins of the flood study terrain data. (Source: FEMA Guidelines and Standards for Flood Risk Analysis and Mapping.)

This data consists of a composite inundation hazards layer for counties from TX to ME, which have a flood exposure snapshot. The dataset was developed from a union of FEMA flood hazard, USACE hurricane evacuation study, NOAA sea level rise of 3-ft above MHHW, and NOAA Shallow Coastal flooding georeferenced digital data. The source and date have been preserved for each source dataset in the attribution. A unique identifier for each hazard, a total number of hazards and hazard description list in the attribution provide coastal risk exposure for each polygon

This layer is sourced from maps.coast.noaa.gov.

This map service presents spatial information developed as part of the National Oceanic and Atmospheric Administration (NOAA) Office for Coastal Management’s Coastal Flood Exposure Mapper. 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 the Coastal Flood Exposure Mapper covers U.S. coastal areas along the Gulf of Mexico and Atlantic Ocean. NOAA provides the information “as-is” and shall incur no responsibility or liability as to the completeness or accuracy of this information. NOAA assumes no responsibility arising from the use of this information. For additional information, please contact the NOAA Office for Coastal Management (coastal.info@noaa.gov).

© NOAA Office for Coastal Management