Use our Predictive Flood Mapping 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.
Overview
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FEMA data alone poses many challenges for renewable developers: Data is missing online for many counties, the data is outdated, doesn’t consider forward-looking risk due to climate change, and FEMA flood zones are shaped by multiple forces leading to inconsistencies in which areas are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 have a partnership with First Street to offer their comprehensive flood risk data as a premium add-on in Prospect.
Users can purchase the data by state (or nationwide package) and the data is integrated right into the Buildable Area Analysis tool with Predictive Flood Mapping from First Street. 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 Predictive flood mapping 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- FEMA flood maps are out of date: 72% of maps are out of date and 11% date back to the 70s and 80s.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.
Predictive Flood Mapping includes access to flood risk layers for the future so you can see how flood risk changes over time. 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 Predictive Flood Mapping work in PVcase Prospect?
See our full workflow documentation on how to run the Buildable area analysis and use the Predictive flood mapping layers.
In addition to being able to analyze the layers as part of the Buildable Area analysis, the same layer
Users can subscribe to predictive flood mapping for specific states or nationwide. Users will then receive access to a premium flood data via two tools within PVcase Prospect.
Pricing
Pricing varies by state and there's a discount for nationwide package. For more details, please reach out to us.
FAQs
How does your Predictive Flood Mapping (First Street) 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's modeling), these 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'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.
Definitions of flood data
The First Street 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).
To learn more, see this FEMA article: Flood maps and zones explained.
What is First Street's methodology for flood modeling and calculating flood risk?
Visit Flood Model Methodology to learn all about First Street Foundation's technical methodology.
Does First Street 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'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'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 2025 and 2055 layers reference climate baseline data from the respective years, but the model was released in March 2025.