AO Premium Flood

Use our premium flood data as a first point of due diligence to understand if there is any flood risk at a site before investing further time and money into a site.


We know analyzing flood risk using FEMA data alone poses many challenges for renewable developers: Data is missing online for many counties, the data is outdated, doesn’t consider forward-looking risk due to climate change, and FEMA flood zones are shaped by multiple forces leading to inconsistencies in which areas are deemed flood risks.
That’s why we’re excited to launch a partnership with First Street Foundation to offer their comprehensive flood risk data as a premium add-on in AO.
Users can purchase the data by state (or nationwide package) and the data is integrated right into the Buildable Area Analysis tool with Premium Flood Data from First Street Foundation. FEMA has significant gaps in online coverage and this leaves renewable developers in the dark about potential site feasibility, risk, and insurance costs. Our premium flood data has coverage for 100% of counties in the U.S. including all counties where FEMA does not have coverage.

Why invest in premium flood data over public FEMA data alone?

  • FEMA has significant gaps in online coverage and this leaves renewable developers in the dark about potential site feasibility, risk, and insurance costs. The map below highlights counties that FEMA does not have flood coverage for online.
    • Our premium flood data has coverage for 100% of counties in the U.S. including all counties that FEMA does not have coverage for.
  • FEMA flood maps are out of date: 72% of maps are out of date and 11% date back to the 70s and 80s.
    • Our partner's models are up-to-date and are considerably more comprehensive in analyzing current and future flood risk.
  • FEMA only looks at historical flooding events and does not account for any future environmental changes.
    • Our premium flood data includes access to flood risk layers for 2050 so you can see how flood risk changes in the future. While some portions of the country have dramatic increases in risk, others have reduction of risk. Overall, the model shows an additional 10.9% or 1.6 million properties as having that 1% or greater annual risk by 2050.
  • FEMA flood zones are shaped by multiple interests (local leaders, business interests) and do not necessarily reflect real flood risk resulting in compromised flood maps.

How does premium flood data work in AO?

See full workflow documentation on how to run the Buildable Area Analysis and use the premium flood layers.
Users can subscribe to premium flood data for specific states or nationwide. Users will then receive access to a premium flood data via two tools within AO:
  • Buildable Area Analysis: Automatically analyze flood risk and create automated constraint maps based on premium flood data via the Buildable Area Analysis tool, by selecting a maximum allowable flood water depth (defaults to zero allowable depth) in each flood area:
    • 100-year flood risk (2020)
    • 500-year flood risk (2020)
    You can still run analysis on FEMA data as well (if FEMA has coverage at the site) so you can compare the flood risks from both models.
  • Layer Overlays: You will have access to the premium flood data via layers in the layers menu that may be overlaid on any map. These layers show expected flood water depth at all locations in the 100-year and 500-year flood event areas and include layers for future-looking flood risk 30-years out in 2050.
    • 100-year flood risk (2020)
    • 500-year flood risk (2020)
    • 100-year flood risk (2050)
    • 500-year flood risk (2050)


Pricing varies by state and there's a discount for nationwide package. Please reach out for details: [email protected]

Frequently Asked Questions: Premium Flood Data

How does your premium flood data (First Street Foundation) categorize 100-year and 500-year flood areas vs FEMA's flood zones?

Beyond some of the modeling methodology differences (read more about First Street Foundation's modeling), theses sources also handle flood 'zones' differently.
FEMA Flood Zones are provided as geographic areas sharing common characteristics related to flooding, primarily the chance of flooding occurring in a given time period.
First Street Foundation's flood data instead estimates flooding depth at any given point in the United States. The data includes an estimate of flooding depth for a 100-year flood event and for a 500-year flood event. In many areas, the estimated flooding depth is 0, or no flooding. The advantage of providing the estimated flood depth rather than a zone is that the user of the data can make their own assessment of what level of flooding depth is acceptable for their project. It also allows users to see detailed flood information for a given area compared to FEMA flood zones which are generalized.
FEMA 100-year and 500-year flood zones
First Street Foundation 100-year and 500-year flood risk layers highlight more nuanced area and include expected flood water depth.
Definitions of flood data: The First Street Foundation Flood Model is a nationwide probabilistic flood model that shows the risk of flooding at any location in (all 50 states) due to rainfall (pluvial), riverine flooding (fluvial), and coastal surge flooding.
FEMA Flood Zones are areas identified on the Flood Insurance Rate Map are identified as a Special Flood Hazard Area (SFHA). SFHA are defined as the area that will be inundated by the flood event having a 1-percent chance of being equaled or exceeded in any given year. The 1-percent annual chance flood is also referred to as the base flood or 100-year flood. SFHAs are labeled as Zone A, Zone AO, Zone AH, Zones A1-A30, Zone AE, Zone A99, Zone AR, Zone AR/AE, Zone AR/AO, Zone AR/A1-A30, Zone AR/A, Zone V, Zone VE, and Zones V1-V30. Moderate flood hazard areas, labeled Zone B or Zone X (shaded) are also shown on the FIRM, and are the areas between the limits of the base flood and the 0.2-percent-annual-chance (or 500-year) flood. The areas of minimal flood hazard, which are the areas outside the SFHA and higher than the elevation of the 0.2-percent-annual-chance flood, are labeled Zone C or Zone X (unshaded). Flood Zones Explained:

What is First Street Foundation's methodology for flood modeling and calculating flood risk?

Read all about First Street Foundation's technical methodology here.

Does First Street Foundation consider recent outlier flood events/recent historical flooding when calculating flood risk?

Yes. First Street Foundation uses historic observation of recent flooding to define likelihoods and then use their hydrodynamic model to decide on depths with those likelihoods.

Why do First Street Foundation's 100- and 500-year layers overlap, while FEMAs 100-year and 500-year flood zones do not?

This is due to the differences between the data described above. First Street Foundation's model for a 500 year flood naturally includes most areas of a 100 year flood. There are some exceptions just because the models aren't perfect. FEMA however breaks areas into Zones and the areas do not overlap. Its is understood that if you are in a 100 year flood zone, that you are also in a 500 year flood zone. The insurance requirement in a 100 year zone is going to be higher than in a 500 year zone, so it's less important for an area to be technically in both zones.

What is the vintage of the First Street Flood layer data?

The 2020 and 2050 layers reference climate baseline data from the respective years, but the model was updated in 2022.