Three Southwest Florida cities may be significantly underestimating their flood risk, according to new data produced First Street Foundation’s Flood Factor model.  The Flood Factor model identified that in Cape Coral, Port Charlotte, and Lehigh Acres the FEMA model used by the National Flood Insurance Program may be undercounting the risk for flooding for more than 80,000 homes — imperiling homeowners by creating a false sense of security, which likely leads them not to purchase flood insurance coverage.

City

Additional Properties at Risk

Share of Properties at Risk

FEMA versus First Street

Cape Coral, FL

41,096

37.8%  → 69.5%
Port Charlotte, FL

20,756

33 %    → 79.3%
Lehigh Acres, FL

20,063

 5%  →  21.1%

Source- New York Times https://www.nytimes.com/interactive/2020/06/29/climate/hidden-flood-risk-maps.html

The First Street Foundation’s flood model uses federal elevation, rainfall data, and coastal flooding estimates from hurricanes, and checks them against historic flood claims.  It also incorporates environmental changes associated with a changing climate, such as sea-level rise and precipitation under a low, median, and high curve of the RCP 4.5 carbon emissions scenarios to calculate current and future flood risks.  See https://firststreet.org/flood-lab/research/flood-model-methodology_overview/   Flood Factor thus produces a probability model of inundation at different flood depths over a 30-year mortgage period at the level of each individual property.  As the chance of a household being impacted by flood better understood not at an annual level, but rather of the extended period of ownership, their report calculates a cumulative probability over 5, 15, and 30 years.

Information transparency is viewed as critical in risk and economic decision making.  The more information is available to buyers and seller, the more likely prices will reflect value.  As homes and property make up a large percentage of the average household’s net worth, it is important for property owners to understand hazard risk factors and mitigate them through structure investment or insurance coverage. Likewise, accurate information on relative flood risk would adjust property values, rewarding home in safer locations.