When commercial real estate transactions close, flood risk due diligence typically begins and ends with FEMA flood maps, documents often decades out of date and focused primarily on riverine flooding. According to Albert Slap, founder of RiskFootprint™, this approach creates significant gaps in understanding actual property vulnerabilities. "FEMA flood maps don't include heavy rainfall flooding," Slap says. "They're mostly dealing with riverine-type flood risk." This distinction matters enormously because wherever it rains, it can flood, creating risks that traditional due diligence methods may completely miss.
The limitations of FEMA maps became dramatically apparent during Hurricane Harvey in 2017, which flooded approximately 150,000 Houston-area homes, 70% of which were located in FEMA's X Zone designated as lower risk for flooding. This extreme, non-riverine rainfall event overwhelmed drainage systems and caused widespread flooding in areas where most property owners did not carry National Flood Insurance Program (NFIP) coverage. The result was an estimated $125 billion in total damages, disproportionately affecting households and businesses that believed they were in low-risk areas based on FEMA designations.
Real property buyers and lenders face the same problem at scale, with credit officers often working from FEMA maps that predate recent storm events, exclude rainfall-driven inundation entirely, and do not incorporate NOAA storm surge modeling advancements from the last decade. To address this due diligence gap, RiskFootprint™ integrates flood models and maps from Fathom/Swiss Re, used by global insurers and reinsurers, to expand on what FEMA provides. The platform available at https://riskfootprint.com adds pluvial, or rainfall-driven, flood modeling alongside riverine and coastal surge scenarios, giving stakeholders a more complete picture of property-level flood exposures before transactions close.
Beyond flood exposure data, RiskFootprint™ now includes estimated first-floor elevation data from True Flood Risk's AI tool, which uses Google Street View and other imagery with artificial intelligence and machine learning to provide estimated first-floor heights on more than 300 million U.S. buildings. This allows the platform to move from mere flood exposure to actual flood vulnerability assessment, distinguishing between buildings that sit two feet above a flood line and those that sit six inches below it.
While FEMA maps serve important functions in NFIP insurance and local building codes, consultants relying solely on them as the complete flood picture for a property are working with only one piece of a larger puzzle. To both assist stakeholders with understanding comprehensive flood risks and protect consultants from future errors and omissions claims, Slap argues for conducting full-spectrum flood assessments before deals close. These assessments should account for all ways water reaches buildings, not just scenarios FEMA mapped decades ago. RiskFootprint™ risk assessment reports are available for a few hundred dollars per property, making comprehensive flood due diligence accessible on virtually any transaction, residential or commercial.
