If you believe your property’s FEMA zone is incorrect, a flood control feature is missing, or you have more information about a historic flood please reach out to us!
Flood Factor® is a free online tool created by the nonprofit First Street Foundation® that makes it easy for Americans to find their property’s risk of flooding and understand how flood risks are changing because of a changing environment. First Street Foundation’s flood model is, built upon the excellent work of FEMA, NOAA, NASA, USGS, and many others, as well as the established and peer-reviewed work of all of our flood model partners. Please let us know if RiskFactor.com is displaying an incorrect FEMA zone, a flood control feature is missing, or if you have additional information regarding the impact of a historic flood. We are continuously working to refine our flood model methodology and incorporate new information into Flood Factor to ensure we are providing the best, most accurate picture of flood risk to our users.
The projections shown on Flood Factor come from the First Street Foundation Flood Model. We have made our flood model’s full technical methodology available to the public because we support scientific collaboration and data transparency. Like all flood models, its projections are intended to help provide a fuller understanding of flood risks, and we encourage you to supplement this information with additional data. We are committed to the accuracy of our data and will continue to grow, adapt, and incorporate feedback and expand our model over time, including an annual data update.
Data that will help improve the Flood Model
You know your property better than anyone! If you have information you think might be helpful to improve our Flood Model, please let us know by submitting a request through our contact forms. Please note that this information will not change your property's Flood Factor, but it can help improve the accuracy of the First Street Foundation Flood Model, and the information shown on Flood Factor. In order to improve our Flood Model, please reach out if you notice any of the following issues:
Incorrect FEMA Zone
If you believe Flood Factor has listed the incorrect FEMA flood zone for your property, please submit a Letter of Map Amendment (LOMA). The FEMA zone information listed on Risk Factor™ is currently an estimated zone. We recommend working directly with an outside company to acquire the Flood Determination Certificate for a property or to get the determinations reversed with a Letter of Map Amendment. Once submitted through our help center form, we can correct this information.
Missing flood control features
Our team is continuing to conduct research on flood control projects around the country and will be continually updating the model based on new information. While our database contains 23,000 features today, we acknowledge there are more to include, and value your input!
If you have knowledge of specific completed projects, precise service area extents-of-flood adaptation infrastructure, or spatial data on flood adaptation infrastructure, please help the team by providing any level of detail you can here. Certain information about flood control projects are particularly useful, such as:
- Name of the flood control project
- Entity in charge of the project (local government, FEMA, USACE, etc.)
- Address or specific location
- Links to local, state, or federal documents outlining project details, including the flood event it protects for
- A map showing the geographic area the project protects, including the physical location of the flood control project
New projects can be included for our next update to improve the model! If you would like to read about examples of flood control projects and how gray infrastructure works to alleviate flooding please review this article.
Example of a levee; an embankment built to prevent the overflow of a river. Levees can also be built along low-lying coastal areas.
Missing historic flooding event
Flood Factor uses data from the First Street Foundation, which has modeled 57 major river and storm surge floods in the U.S. from 2001 on, and is continually adding more. Historic events in the First Street Foundation Flood Model are recreated using hydraulic models and public data sources. Historic river flooding events are recreated by analyzing historical USGS stream gauge readings during identified flood events and then compared to recorded high water marks and insurance claims of flooding made during that event. Coastal flooding events are recreated by analyzing storm surge, tides, coastal circulation, wind-generated waves, and geospatial analysis for specific storms, such as Hurricane Katrina. The recreation is then compared to recorded high water marks during the event.
Aftermath of Hurricane Gustav - August 2008
If you have knowledge of specific historic flooding, we'd love to hear from you. We will investigate historic flooding this area further and incorporate any new events determined into our future update.
In order to include historic events in our Flood Model please reach out to us through our Help Center and provide:
- Dates the event took place
- Location of historic flooding
- Any pictures that may show the depth and damage of the flood
- News articles that describe the flooding your property experienced
We understand you may have questions regarding names of locations related to your property. The First Street Foundation Flood Model matches parcel data from official government sources to address data collected from commercial sources. Naming conventions attached to specific parcels and addresses may not exactly match, resulting in naming discrepancies. Here is a link to the methodology behind our research.
If you have knowledge of specific location names, we'd love to hear from you. Please submit a ticket through the Risk Factor Help Center that includes:
- A corrected address that includes the house number, street address, zip code, city, and state
- The incorrect address listed on FloodFactor.com
We will review the issue further and be sure to update any issues found during a future update. Please take a look at how we update Risk Factor data.
Flood Model Methodology - Calculating property-level risk