Jeremy Porter, professor of sociology at City University of New York. He is currently the director of quantitative methods for the social sciences program at Cuny Graduate Center and is the assistant executive officer of the Graduate Center’s PhD. Sociology program. It was originally published in conversation.
Fatal and devastating flash floods in Texas and several other states in July 2025 raises questions about the country’s flood maps and the ability of communities and homeowners to reorganize what they can prepare for increased risk.
The same area of Texas Hill Country, where the July 4 flash flood killed at least 129 people, was hit again in a downpour a week later, with searchers temporarily halting efforts to find the missing victim. Other states, including New Mexico, Oklahoma, Vermont and Iowa, also experienced flash floods in July.
The US Federal Emergency Management Agency’s flood map is intended to be the country’s primary tool for identifying flood risk. Originally developed in the 1970s, to support the National Flood Insurance Program, it is used to determine where flood insurance needs a strategy using flood insurance rate maps or maps known as companies.
In theory, this map has led homeowners, businesses and local officials to understand flood risk and take good measures to prepare and mitigate potential losses.
The federal flood map in Kellville, Texas shows areas where the Guadalupe River is engulfed in a purple center, where it is believed to be possible annual flooding in blue with 1% flooding and 0.2% sunburn. During the flash flood on July 4, 2025, the river rose over 30 feet in Kellville. FEMA
However, FEMA uses better data, digital tools and community input to employ map accuracy and accessibility over time, but the map does not capture everything, including changing climates. There are areas of the country that regularly flood subdra and do not appear on the map as they are at risk.
I am studying flood risk mapping as a university-based research and at First Street, an organization created to quantify and communicate climate risk. In 2023 donkeys using newly modelled flood zones with climate-adjusted reading records, more than twice as many properties across the country were found to have a 100-year flood risk than the FEMA map was identified.
It was found that even where FEMA maps identified flood risks, relying on federal mapping processes, historical data, and political influencing map updates could lead to maps that do not fully represent local risks.
What FEMA Flood Maps miss
FEMA maps are an essential tool for identifying flood risks, but there are important gaps that limit their effectiveness.
One major limitation is that it is considered a flood driven by a heavy burst of rain. The map focuses primarily on river channels and coastal flooding, largely excluding the risk of flash flooding, particularly along small channels such as streams, streams and tributes.
This limit has more important scholarships in recent years due to climate change. Global temperature rises can cause more frequent, extreme heavy rains, making more areas vulnerable to flooding, but not covered by FEMA.
A map of the section of Kerr County, Texas, where the fatal flood occurred on July 4, 2025 compares the 100-Year Flood Zone (red) of the FEMA Flood Map with the more detailed 100-Year Flood Zone (blue) of Grace Street. The more washed map includes the risk of flash floods along streams and streams. Jeremy Porter
For example, in 2024, when floods from Hurricane Helen collided with a mapping area around Asheville, North Carolina, the property suffered uninsured damage.
Even in mapped areas, such as the Camp Mystic Site in Carr County, Texas, which suffered a fatal flash flood on July 4, 2025, the map could underestimate the beckoning of ESK risks of reliance on historical data and outdated risk assessments.
Political ability can burn length
Additionally, FEMA mapping processes are often shaped by political pressure.
Local governments and developer subti fight to avoid high-risk designations to avoid insurance delegation or development restrictions, leading to maps that may hold back current risks and entrust residents with exposure.
An example is the appeal of the 2015 FEMA Flood Insurance Price Map for New York City. The delay in the city’s concerns remained maps from around 20 years ago, leaving the current mapping project tied to a legal deficit.
At Avenge, it will take five to seven years to develop and implement a new FEMA flood insurance premium rate map. As a result, many maps have made the United States significantly outdated with ACROS and often fail to imagine flood risk from current land use, urban development, or extreme weather conditions in Extm.
This delay directly affects building standards and infrastructure planning as local governments reassess the SECE map to guide construction standards, development approvals and flood mitigation projects. Ultimately, outdated maps could lead to vulnerable ones that underestimate the risk of flooding and allow structures to be built in areas facing increased flood threats.
How advances in technology can help
New advances in satellite imaging, rainfall modeling and high-resolution lidars are similar to radar, but using light allows for faster and more accurate flood maps to capture risks from extreme rainfall and flash floods.
However, fully integrated these tools require significant federal investment. Congress will manage FEMA mapping budgets and establish a legal framework for how maps are created. For years, updating flood maps has been an apoplar topic among many publicly elected officials. This is because new flood designations can cause stricter building standards, higher insurance costs and development restrictions.
The Houston map was created for research in 2022 by university and First Street researchers, showing that flood risk will change over the next 30 years as climate change worsens. The blue area is today’s 100-year flood risk zone. The red area reflects the same zone in 2050. OliverWinget al. , 2022
In recent years, the rise in climate risk analysis models and private flood risk data have made the real estate, finance and insurance industries less dependent on FEMA maps. These new models generally exclude extreme rainfall predictions, sea level rise, and maps of changing storm pattern factors FEMA.
Real estate portals such as Zillow, Redfin, Realtor.com and Homes.com have now become real estate-level flood risk scores taking into account both historic flooding and future climate forecasts. The models they use identify the risks of many properties that do not have FEMA maps and highlight hidden vulnerabilities in US communities.
Research shows that climate data is available and accessible for the first sites that have begun to drive property purchase decisions that will take into account climate change more and more.
Impact on the future
Home buyers have a better understanding of the flood risk of their property, and thus may change the desirability of sub-sublocations over time. These shifts affect property valuations, community tax revenue valuations, population movement patterns, and many other considerations.
However, while these may seem like new data is changing the changes purchased, the risks were already there. It is the people’s awareness that is changing.
The federal government plays an important role in responsing that accurate risk donkeys are available to communities and Americans everywhere. As better tools and models evolve to assess risk occurrence, so will FEMA risk maps.
