What is my Advisory Base Flood Elevation (ABFE)?

As communities, residents and business owners along the coastlines of New York and New Jersey begin to recover from the effects of Hurricane Sandy, it is important for individuals to understand their flood risk.  The Federal Emergency Management Agency (FEMA), as the administrator of the National Flood Insurance Program (NFIP), has prepared Advisory Base Flood Elevations (ABFE) utilizing on-going coastal studies that were underway for the North Atlantic Coast prior to Hurricane Sandy.  This advisory information will provide the communities, residents and business owners in the ABFE mapping area with more precise information about the flood risk they face, allowing them to make more informed decisions to reduce their personal risk to life and property.This may have you wondering…
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What is My Property’s ABFE?

The interactive tool below can assist you in determining the current and advisory flood risk of your property*.  To find out what information is available for your property, follow these three easy steps:
1.    Enter your address into the field below and click the “Get Details” button. Internet Explorer users: You must click‘No’ if a security warning pop up window appears on your screen in order for information to display correctly in the report after clicking the “Get Details” button.
2.    A “flag” (graphic) will be added to the map banner below indicating the location the tool will provide information at.  Find your home on the map and click on your house.
3.    The data fields below the map banner will provide you with an overview of ABFE and related information at the location you placed the flag (graphic).  Print the report and take it to your local building and permitting authority to understand the building requirements for your property.
Below the report, you will find information on what you can do with the ABFE information.  For more detailed information about ABFEs visit the Hurricane Sandy ABFE Homepage and read the ABFE FAQ.
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*DISCLAIMERThe information generated on each report is dependent on the location of the point location of the flag (graphic). The flood information included in the report tables below is not a determination. Results from the What is My ABFE Tool are not intended for insurance rating purposes and is for information only. The positional accuracy may be compromised in some areas. The address locator is not 100% accurate in identifying your address. Property owners should contact your local floodplain administrator for more information or to view an official copy of the Flood Insurance Rate Maps and discuss the ABFEs in the vicinity of their property prior to starting any reconstruction activity.
 
If you have any questions about what you are looking at, click with your mouse on the hyperlinked question in the left column and a glossary will provide you a definition of what is being described.
What Does it Mean if the Report shows ‘N/A’ for All Fields?    
The ‘What is my ABFE’ tool will return ‘N/A’ results in 2 situations: 1) in cases where ABFE data is not yet available for a location and 2) in cases where the location is not in an Advisory flood zone.  ABFE data has been released for the following counties to date:  Atlantic, Bergen, Burlington, Cape May, Essex, Hudson, Middlesex, Monmouth, Ocean, and Union (New Jersey).  Therefore, if your property is located in one of these counties and you receive ‘N/A’ results, it is most likely you are not located in an Advisory flood zone. 
If you click on the ‘Link to Web Tool’ in the report, it will bring up the ABFE map for your location – this is an easy way that you can see your location on the map and any flood zones in the vicinity.  Even if you are not actually located in an Advisory flood zone, you should still consider purchasing flood insurance if you are close to an Advisory flood zone to reduce the chance of financial impacts in case a flood does occur in the future.
Base Flood Elevation Map
What Should I Do With The ABFE Information in the Report?    
As you make decisions for rebuilding and reconstruction, the information provided by the What is My ABFE Tool will provide you an understanding of the possibility of flooding and coastal wave actions that affect your property.  Investigations conducted by FEMA and other organizations after major coastal disasters have consistently shown that properly sited, well-designed, and well-constructed coastal residential buildings generally perform well. This information can assist you in your rebuilding efforts and provides a centralized point of risk information for you to discuss permitting requirements with your local building and permitting staff.•    Local building and permitting varies by community. This information will allow you to meet with your local building and permitting authority to discuss your individual property building requirements.•    Before building, property and business owners should consult their local government officials to determine the mandatory elevations and any construction requirements for their home or building.•    Consider elevating your home’s lowest floor above the Base Flood Elevation.  Elevating your structure is a good way to reduce your risk of flooding even if your property is not currently subject to flooding.•    Elevating your home above the Base Flood Elevation or Advisory Base Flood Elevation (whichever is higher) will also provide a future reduction in flood insurance premiums.•    If your property is subject to coastal wave action, consider breakaway walls and other structural building measures that will allow the building to remain after a storm event.•    Consider relocating your structure (if possible) to minimize the hazards your home or business may encounter.Visit the ABFE Toolkit for Property Owners webpage for answers to common questions about the ABFEs and helpful fact sheets and websites regarding ABFEs, rebuilding, flood insurance and other topics.Questions or comments?  Call the National Flood Insurance Program Help Center at 1(800) 427-4661 or contact us through our online form today.

Under its Risk MAP Program, the Federal Emergency Management Agency (FEMA) is providing quality flood hazard information to help communities plan for and reduce the risk from flooding. As part of that effort, the FEMA Region II office has initiated a coastal flood study to update the information shown on the Flood Insurance Rate Maps (FIRMs) for 14 coastal New Jersey counties and New York City. The FIRM shows each community’s flood hazards and is a requirement for participation in the National Flood Insurance Program (NFIP).  The FIRM is used to determine who must buy flood insurance and where floodplain development regulations apply.
For additional information, the FEMA website, which will be updated as progress on the coastal flood study continues, will include links to the online preliminary FIRM panels (once completed), and details on public meetings to review those preliminary results. We encourage you to explore this website to learn more - be sure to check back regularly for updates. In the meantime, there are steps that you can take now to keep your communities and families safe from flood risk: 
Know your risk – Understand the risk of flooding in your area.View your community’s current flood hazard maps and check back here for updates on the project underway. View  Advisory Base Flood Elevation (ABFE) information being developed by FEMA to help communities, property owners and others make informed decisions about rebuilding in the aftermath of Hurricane Sandy.
 
Know your role – Understand the role you play when disaster strikes and how you can reduce the impact flooding has on you and your loved ones, your property, and your community. VisitReady.gov (or Ready New York for New York residents) to learn about ways to get prepared and FloodSmart.gov for more information on flood risk and flood insurance. 
 
Take action – Visit Ready.gov (or Ready New York for New York residents) to learn how to get prepared. Then, tell others about your community’s flood risk and what steps they can take to keep safe from flooding.

Coastal Mapping Basics

Image of waves breaking along the New Jersey shoreline

Introduction

The effects of tides, combined with large amounts of water and waves from storms make coastal areas some of the most at-risk areas when it comes to flooding.  To identify and map coastal flood hazards accurately, many factors must be taken into account, such as the amount of development in the area, the types and strength of storms that historically have affected the area, and the onshore and offshore topography.  This section provides an overview of the steps involved to identify and map the coastal flood hazards shown on the FEMA Flood Insurance Rate Map (FIRM).  The FIRM is used to determine flood insurance requirements for residents and where floodplain development regulations apply in a community.

Image of beach sand along the New Jersey coast

Special Flood Hazard Areas and Base Flood Elevations

Each FIRM shows Special Flood Hazard Areas (SFHAs), or the areas subject to flooding by a storm or flood event that has a one percent chance of being equaled or exceeded in any given year.  The SFHA includes all ‘A’ and ‘V’ FIRM zones, the most common being:  A, AO, AH, AE, VE, and V.  For a full listing of flood zones with detailed descriptions, visit FEMA’s Flood Zones webpage.  Insurance rates and building requirements are tied to SFHA boundaries and the Base Flood Elevations (BFEs) that are established for these areas and shown on the FIRM.  A BFE is the water level expected in the SFHA for a one-percent-annual-chance flood event.  To accurately model and map coastal SFHAs and BFEs, study teams made up of engineers, coastal scientists, surveyors, and mapping specialists conduct coastal flood studies that include storm surge analysis and overland wave modeling.  The process is described below.

 Image of a mesh, or high resolution grid, developed when modeling storm surge using the ADCIRC computer model.

A mesh, or high resolutiongrid, developed when modeling storm surge using the ADCIRC computer model.

Coastal Storm Surge Analysis

Coastal flooding is usually caused by coastal storms, including tropical storms, hurricanes, and nor’easters.  Storm surge is the amount of water, combined with the effect of normal tides that is pushed towards the shore during a storm.  The height of the storm surge is driven by many variables, such as the strength and size of the storm, as well as how quickly and the direction in which the storm moves.  Using information from historical storms that have affected the study area, a representative set of storm events are determined and then modeled.  The storm surge elevations generated from this model are then used to determine the probability of a storm surge event of a given magnitude (for example, a storm that has a one percent chance of occurring in a given year).Storm surge analyses for FEMA coastal flood studies are often performed using the ADCIRC (ADvanced CIRCulation) coastal circulation and storm surge computer model in conjunction with the Simulating Waves Nearshore (SWAN) computer model.  Once complete, the storm surge analysis will result in the development of stillwater elevations for the one-percent-annual-chance flood event.   A stillwater elevation does not take into account all effects from waves coming ashore during a storm event.  Therefore, a separate overland wave modeling analysis is needed in addition to the storm surge analysis to accurately determine coastal SFHAs and BFEs.

Overland Wave Modeling

In addition to storm surge, waves play an important role in coastal flooding.  An overland wave modeling analysis is required to fully evaluate the effect that waves have on coastal areas during a flood event.  FEMA typically uses a computer simulation model called the Wave Height Analysis for Flood Insurance Studies (WHAFIS) to perform overland wave modeling.  This model takes into account water depth, wind speed, vegetative cover, building density, and other factors to predict the heights of waves, which plays an important role in determining coastal BFEs and flood zones.  Wave runup and wave setup (discussed below) are also important factors in overland wave modeling.
Wave runup. The rush of water that extends inland when waves come ashore is called ‘wave runup.’  The overland wave analysis will determine the elevations to which wave runup extends during a storm event.  These elevations may be higher than the stillwater elevations computed as part of the storm surge analysis.

Wave setup. In addition to the effects of wave runup and the computed storm surge stillwater elevation, there is also an increase in the water level caused by waves breaking ashore during a storm event.  This increase in the water level is called ‘wave setup’, which can be a significant factor in determining coastal BFEs.  Wave setup is affected by the height of the waves, the speed at which waves approach the shore, and the slope of the ground near the shore.

Erosion (or, the removal of soil) due to storms and the presence of coastal structures, such as seawalls are also taken into account when overland wave modeling is performed.

  A diagram showing the coastal storm surge stillwater elevation and how it relates to wave setup and wave runup effects.
The coastal storm surge stillwater elevation (SWEL) and
the added effects of wave setup and wave runup.

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Detail of a coastal Flood Insurance Rate Map

Detail from a coastal FIRM.

Mapping Coastal Hazards

Once the coastal storm surge analysis and overland wave modeling are complete, the most up-to-date topographic information available will be used to map the coastal SFHA boundaries based on the results of these analyses.  BFEs will also be added to the FIRM at this point in the mapping process. The different flood risk zones that comprise the coastal SFHA – ‘V’ zones and ‘A’ zones (described below), will also be delineated.

Coastal High Hazard Areas (V Zones)

Coastal high hazard areas, designated as V zones on the FIRM, are the areas of the coastal floodplain subject to the highest risk.  Typically, this is the area where the computed wave heights for the base (one-percent-annual-chance) flood are 3 feet or more.  V zones are subject to more stringent building requirements and different flood insurance rates than other zones shown on the FIRM because these areas are exposed to a higher level of risk than other coastal flooding areas.

Coastal A Zones

Portions of the SFHA landward of a V zone (i.e., areas where wave heights are computed as less than 3 feet) are mapped as ‘A’ zones on the FIRM.  While the wave forces in coastal A zones are not as severe as those in V zones, the capacity for the damage or destruction of buildings is still present.
Diagram:  The Coastal Flood Zone
 
V zones are portions of the SFHA where wave heights are greater than three feet.  These areas are subject to more stringent building requirements than coastal A zones because the risk from coastal flooding is greater.
 
Coastal BFEs take into account both the storm surge ‘stillwater’ elevation and additional effects from waves.  

Limit of Moderate Wave Action

An additional area that may be shown on coastal FIRMs for informational purposes is the Limit of Moderate Wave Action (LiMWA).  The LiMWA identifies areas that will be affected by waves with a 1.5 foot wave height or greater within the coastal A zone.  While FEMA currently does not require special floodplain management standards or flood insurance purchase requirements based on LiMWA delineations, it is likely that properties and structures within the LiMWA will receive substantial damage from wave action during a one-percent-annual-chance flood event.  As a result, communities are encouraged to adopt the more stringent building construction standards applicable for V Zones in these areas.
Diagram:  The Limit of Moderate Wave Action (LiMWA) 
 
The LiMWA is the area within the coastal A zone where wave heights are between 1.5 and 3 feet.  These areas will likely be subject to substantial damage during a one-percent-annual chance flood event. 
A diagram indicating the different FEMA coastal flood mapping zones, including the V zone, A zone and Limit of Moderate Wave Action area.

Learn More

More information about the nation’s coastal resources, including additional information on coastal flood risk and storm surge, can be found on NOAA’s State of the Coast website or through the Jacques Cousteau National Estuarine Research Reserve online Coastal Training Program.  For general questions about FEMA flood hazard mapping, contact the FEMA Map Information eXchange.  For specific questions about the New Jersey and New York coastal flood study, contact us through our online form.

Information for Disaster Survivors and Recovering Communities

FEMA continues to lead the Federal government’s effort to provide assistance and support to States affected by Hurricane Sandy, ensuring Federal agencies and their public and private partners continue to provide all available resources toState, local, and tribal communities in affected areas. This page lists helpful resources to support recovery and rebuilding efforts by individuals, business owners and communities affected by Sandy.

General Information

FEMA’s Hurricane Sandy homepage provides the latest information on available FEMA assistance and recovery initiatives with materials in nine different languages.  Additional information for New Jersey residents is available through the State of New Jersey’s Hurricane Sandy Information Center.  Additional information for New York residents is available through the NYC Severe Weather webpage.

Information is also available from FEMA about the disaster processdisaster aid programshazard mitigation grant and loan programs and FEMA’s whole community approach to emergency management.

To learn more about FEMA’s National Flood Insurance Program (NFIP) or to find an insurance agent, visit FloodSmart.govor call 1-888-229-0437. If your home or business has been damaged by flooding, you may be required to meet certain building requirements in your community to reduce future flood damage before you repair or rebuild.  To help you cover the costs of meeting those requirements, the NFIP makes available Increased Cost of Compliance (ICC) coverage for all new and renewed standard flood insurance policies.  Additional information about ICC coverage is available in the following brochure:

Increased Cost of Compliance:  How You Can Benefit

On July 6, 2012, a law took effect that made significant reforms to the NFIP.  The fact sheet Changes in the Flood Insurance Program:  Preliminary Considerations for Rebuilding provides additional information on these changes.

 

Advisory Base Flood Elevations and Guidance for Reconstruction Efforts
 

Prior to Hurricane Sandy, FEMA was restudying areas of the New Jersey and New York coastlines to update flood hazards shown on NFIP Flood Insurance Rate Maps (FIRMs) in these areas. These updated maps were set to be delivered to State and local officials in mid-2013. Since existing FIRMs for these areas were developed more than 25 years ago, and because updated FIRMs are yet to be finalized, FEMA believes it vital to provide near-term Advisory Base Flood Elevations (ABFEs) to support rebuilding efforts.

Visit this website’s Hurricane Sandy ABFE webpage for comprehensive information on the availability of ABFEs, how they can be used, and to view and download data once available. Additional information is also available through the ABFE Toolkit for Property Owners page, the ABFE Toolkit for Community Officials page and the ABFE Frequently Asked Questions page.   

To ask questions and get information about flood insurance and ABFEs, call the National Flood Insurance Program Help Center at 1(800)427-4661 or contact us through this website’s online form.

For more information about how to build safer and stronger and to potentially decrease your flood insurance premiums, download the FEMA Hurricane Sandy Building Science fact sheet. More information on recent changes to the NFIP that should be considered when rebuilding is available in the fact sheet Changes in the Flood Insurance Program:  Preliminary Considerations for Rebuilding.

Buildings located in a Special Flood Hazard Area that are determined to be substantially damaged or improved must be brought into compliance with the minimum requirements of the community’s National Flood Insurance Program (NFIP)-compliant floodplain management laws or ordinances.   Communities participating in the NFIP often have difficulty determining whether buildings are substantially damaged.  This difficulty is magnified after a major flood or other disaster where a large number of buildings have been damaged and there is a need to provide timely substantial damage determinations so that reconstruction can begin.  The Substantial Damage Estimator (SDE) software was developed to assist State and local officials in estimating building value and costs to repair residential and non-residential buildings and is available for download at no cost.  The reference document Substantial Damage Estimator Best Practices is also available online.

Before building, property and business owners should consult their local government officials to determine the local building code, permit, and mandatory elevation requirements for their home or building. 

Disaster Assistance

Available assistance can include rental payments for temporary housing, grants for home repairs, low interest loans for small businesses, and more. Information to learn about the types of assistance available and to apply for assistance can be accessed using the following ways:

     - Apply online at http://www.disasterassistance.gov/ or through a mobile device at m.fema.gov.

 
     - Call 1-800-621-FEMA or 1-800-462-7585 (TTY) for hearing and speech impaired.
 
     - Visit a Disaster Recovery Center in your area.

Additional Resources

  • Interactive Maps

 

Questions or comments?  Call the National Flood Insurance Program Help Center at 1(800) 427-4661 or contact us through our online form today.

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