logo
Why FEMA's flood maps often miss dangerous flash flood risks

Why FEMA's flood maps often miss dangerous flash flood risks

Fast Company16-07-2025
Deadly and destructive flash flooding in Texas and several other states in July 2025 is raising questions about the nation's flood maps and their ability to ensure that communities and homeowners can prepare for rising risks.
The same region of Texas Hill Country where a flash flood on July 4 killed more than 130 people was hit again with downpours a week later, forcing searchers to temporarily pause their efforts to find missing victims. Other states, including New Mexico, Oklahoma, Vermont, and Iowa, also saw flash flood damage in July.
The U.S. Federal Emergency Management Agency's flood maps are intended to be the nation's primary tool for identifying flood risks. Originally developed in the 1970s to support the National Flood Insurance Program, these maps, known as Flood Insurance Rate Maps, or FIRMs, are used to determine where flood insurance is required for federally backed mortgages, to inform local building codes and land-use decisions, and to guide flood plain management strategies.
In theory, the maps enable homeowners, businesses, and local officials to understand their flood risk and take appropriate steps to prepare and mitigate potential losses.
But while FEMA has improved the accuracy and accessibility of the maps over time with better data, digital tools, and community input, the maps still don't capture everything—including the changing climate. There are areas of the country that flood, some regularly, that don't show up on the maps as at risk.
I study flood-risk mapping as a university-based researcher and at First Street, an organization created to quantify and communicate climate risk. In a 2023 assessment using newly modeled flood zones with climate-adjusted precipitation records, we found that more than twice as many properties across the country were at risk of a 100-year flood than the FEMA maps identified.
Even in places where the FEMA maps identified a flood risk, we found that the federal mapping process, its overreliance on historical data, and political influence over the updating of maps can lead to maps that don't fully represent an area's risk.
What FEMA flood maps miss
FEMA's maps are essential tools for identifying flood risks, but they have significant gaps that limit their effectiveness.
One major limitation is that they don't consider flooding driven by intense bursts of rain. The maps primarily focus on river channels and coastal flooding, largely excluding the risk of flash flooding, particularly along smaller waterways such as streams, creeks, and tributaries.
This limitation has become more important in recent years due to climate change. Rising global temperatures can result , leaving more areas vulnerable to flooding, yet unmapped by FEMA.
For example, when flooding from Hurricane Helene hit unmapped areas around Asheville, North Carolina, in 2024, it caused a huge amount of uninsured damage to properties.
Even in areas that are mapped, like the Camp Mystic site in Kerr County, Texas, that was hit by a deadly flash flood on July 4, 2025, the maps may underestimate their risk because of a reliance on historic data and outdated risk assessments.
Political influence can fuel long delays
Additionally, FEMA's mapping process is often shaped by political pressures.
Local governments and developers sometimes fight high-risk designations to avoid insurance mandates or restrictions on development, leading to maps that may understate actual risks and leave residents unaware of their true exposure.
An example is New York City's appeal of a 2015 FEMA Flood Insurance Rate Maps update. The delay in resolving the city's concerns has left it with maps that are roughly 20 years old, and the current mapping project is tied up in legal red tape.
On average, it takes five to seven years to develop and implement a new FEMA Flood Insurance Rate Map. As a result, many maps across the U.S. are significantly out of date, often failing to reflect current land use, urban development, or evolving flood risks from extreme weather.
This delay directly affects building codes and infrastructure planning, as local governments rely on these maps to guide construction standards, development approvals, and flood mitigation projects. Ultimately, outdated maps can lead to underestimating flood risks and allowing vulnerable structures to be built in areas that face growing flood threats.
How technology advances can help
New advances in satellite imaging, rainfall modeling, and high-resolution lidar, which is similar to radar but uses light, make it possible to create faster, more accurate flood maps that capture risks from extreme rainfall and flash flooding.
However, fully integrating these tools requires significant federal investment. Congress controls FEMA's mapping budget and sets the legal framework for how maps are created. For years, updating the flood maps has been an unpopular topic among many publicly elected officials, because new flood designations can trigger stricter building codes, higher insurance costs, and development restrictions.
In recent years, the rise of climate risk analytics models and private flood risk data have allowed the real estate, finance and insurance industries to rely less on FEMA's maps. These new models incorporate forward-looking climate data, including projections of extreme rainfall, sea-level rise and changing storm patterns—factors FEMA's maps generally exclude.
Real estate portals like Zillow, Redfin, Realtor.com, and Homes.com now provide property-level flood risk scores that consider both historical flooding and future climate projections. The models they use identify risks for many properties that FEMA maps don't, highlighting hidden vulnerabilities in communities across the U.S.
Research shows that the availability, and accessibility, of climate data on these sites has started driving property-buying decisions that increasingly take climate change into account.
Implications for the future
As homebuyers understand more about a property's flood risks, that may shift the desirability of some locations over time. Those shifts will have implications for property valuations, community tax-revenue assessments, population migration patterns, and a slew of other considerations.
However, while these may feel like changes being brought on by new data, the risk was already there. What is changing is people's awareness.
The federal government has an important role to play in ensuring that accurate risk assessments are available to individuals and communities everywhere. As better tools and models evolve for assessing risk evolve, FEMA's risk maps need to evolve, too.
Orange background

Try Our AI Features

Explore what Daily8 AI can do for you:

Comments

No comments yet...

Related Articles

Castle Biosciences to Present at the Canaccord Genuity 45th Annual Growth Conference
Castle Biosciences to Present at the Canaccord Genuity 45th Annual Growth Conference

Yahoo

time4 hours ago

  • Yahoo

Castle Biosciences to Present at the Canaccord Genuity 45th Annual Growth Conference

FRIENDSWOOD, Texas, July 29, 2025 (GLOBE NEWSWIRE) -- Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patient care, today announced that its executive management is scheduled to present a company overview at the Canaccord Genuity 45th Annual Growth Conference on Tuesday, Aug. 12, 2025, at 12:30 p.m. Eastern time. A live audio webcast of the Company's presentation will be available by visiting Castle Biosciences' website at A replay of the webcast will be available following the conclusion of the live broadcast. About Castle BiosciencesCastle Biosciences (Nasdaq: CSTL) is a leading diagnostics company improving health through innovative tests that guide patient care. The Company aims to transform disease management by keeping people first: patients, clinicians, employees and investors. Castle's current portfolio consists of tests for skin cancers, Barrett's esophagus and uveal melanoma. Additionally, the Company has active research and development programs for tests in these and other diseases with high clinical need, including its test in development to help guide systemic therapy selection for patients with moderate-to-severe atopic dermatitis seeking biologic treatment. To learn more, please visit and connect with us on LinkedIn, Facebook, X and Instagram. DecisionDx-Melanoma, DecisionDx-CMSeq, i31-SLNB, i31-ROR, DecisionDx-SCC, MyPath Melanoma, TissueCypher, DecisionDx-UM, DecisionDx-PRAME and DecisionDx-UMSeq are trademarks of Castle Biosciences, Inc. Investor Contact:Camilla Zuckeroczuckero@ Media Contact:Allison Marshallamarshall@ Source: Castle Biosciences while retrieving data Sign in to access your portfolio Error while retrieving data Error while retrieving data Error while retrieving data Error while retrieving data

Natera Announces Launch of ABCSG 61 ("TEODOR"), a Randomized Controlled Trial of Signatera™ in Early-Stage Breast Cancer
Natera Announces Launch of ABCSG 61 ("TEODOR"), a Randomized Controlled Trial of Signatera™ in Early-Stage Breast Cancer

Yahoo

time4 hours ago

  • Yahoo

Natera Announces Launch of ABCSG 61 ("TEODOR"), a Randomized Controlled Trial of Signatera™ in Early-Stage Breast Cancer

Study utilizes Signatera to identify HR+, HER2-negative breast cancer patients for de-escalation of neoadjuvant chemotherapy AUSTIN, Texas, July 29, 2025--(BUSINESS WIRE)--Natera, Inc. (NASDAQ: NTRA), a global leader in cell-free DNA and precision medicine, today announced the launch of the TEODOR trial (Neoadjuvant TrEatment Optimization driven by ctDNA and endOcrine Responsiveness). TEODOR is a Phase II, multicenter, randomized controlled trial (RCT) that aims to replace chemotherapy with endocrine therapy prior to surgery for a subset of women with hormone receptor-positive (HR+), HER2-negative breast cancer, who are endocrine responsive and test negative with Signatera. Sponsored by the Austrian Breast & Colorectal Cancer Study Group (ABCSG), TEODOR expects to enroll approximately 250 patients across 15 sites in Austria. Previous studies have demonstrated that patients who test Signatera-negative at diagnosis and then receive chemotherapy have excellent outcomes, with risk of recurrence at less than 5%. In an effort to reduce pre-operative chemotherapy, which can carry significant side effects, this study is designed to evaluate the efficacy of endocrine therapy compared to chemotherapy in patients who are Signatera-negative. After a four-week course of endocrine therapy, patients who are Signatera-negative and show a favorable endocrine sensitivity as measured by the Ki-67 proliferation index will be randomized to receive either additional endocrine therapy or chemotherapy. The primary endpoint of the study is the rate of neoadjuvant therapy response, assessed via pathological complete response (pCR) and modified Preoperative Endocrine Prognostic Index (PEPI) score across the endocrine therapy and chemotherapy arms of the trial. Secondary endpoints include long-term outcomes such as breast cancer recurrence and overall survival. "TEODOR is designed to examine whether we can use endocrine responsiveness and ctDNA status to optimize systemic therapy in the neoadjuvant setting," said ABCSG President, Michael Gnant, M.D., FACS, FEBS, who serves as professor of surgery, Comprehensive Cancer Center, Medical University of Vienna, and principal investigator of the TEODOR trial. "This study marks a critical step toward more personalized medicine, leveraging the latest technologies to improve patient care." "With the TEODOR trial, our goal is to identify patients who may be able to safely forgo chemotherapy," said Angel Rodriguez, M.D., medical director of oncology at Natera. "We are proud to collaborate with ABCSG on this important trial, and we hope this study will support the role of Signatera in guiding neoadjuvant therapy in breast cancer." About Natera Natera™ is a global leader in cell-free DNA and genetic testing, dedicated to oncology, women's health, and organ health. We aim to make personalized genetic testing and diagnostics part of the standard-of-care to protect health and inform earlier, more targeted interventions that help lead to longer, healthier lives. Natera's tests are supported by more than 300 peer-reviewed publications that demonstrate excellent performance. Natera operates ISO 13485-certified and CAP-accredited laboratories certified under the Clinical Laboratory Improvement Amendments (CLIA) in Austin, Texas, and San Carlos, California. For more information, visit About ABCSG The ABCSG (Austrian Breast & Colorectal Cancer Study Group) is Austria's largest and best-known academic research organization, successfully conducting international clinical trials on breast and colorectal cancer — and, since 2013, also on pancreatic cancer. In addition, ABCSG is increasingly active in translational research. Our goal is to standardize diagnostics, treatment, and follow-up care throughout Austria and to offer patients the best and most up-to-date therapies. Since 1984, approximately 29,000 patients have participated in ABCSG studies worldwide. Multidisciplinarity is key to our global success and has helped improve cure rates and survival. Our clinical trials and translational research projects are conducted transparently and are monitored at every stage by ethics committees, regulatory authorities, and our highly professional and dedicated ABCSG team. Forward-Looking Statements All statements other than statements of historical facts contained in this press release are forward-looking statements and are not a representation that Natera's plans, estimates, or expectations will be achieved. These forward-looking statements represent Natera's expectations as of the date of this press release, and Natera disclaims any obligation to update the forward-looking statements. These forward-looking statements are subject to known and unknown risks and uncertainties that may cause actual results to differ materially, including with respect to whether the results of clinical or other studies will support the use of our product offerings, the impact of results of such studies, our expectations of the reliability, accuracy, and performance of our tests, or of the benefits of our tests and product offerings to patients, providers, and payers. Additional risks and uncertainties are discussed in greater detail in "Risk Factors" in Natera's recent filings on Forms 10-K and 10-Q, and in other filings Natera makes with the SEC from time to time. These documents are available at and View source version on Contacts Investor Relations: Mike Brophy, CFO, Natera, Inc., investor@ Media: Lesley Bogdanow, VP of Corporate Communications, Natera, Inc., pr@ Sign in to access your portfolio

Turkey's glaciers fall victim to climate change
Turkey's glaciers fall victim to climate change

Yahoo

time9 hours ago

  • Yahoo

Turkey's glaciers fall victim to climate change

Kemal Ozdemir looked up at the bare peaks of Mount Cilo in Turkey's Kurdish majority southeast: "There were glaciers 10 years ago," he recalled under a cloudless sky. A mountain guide for 15 years, Ozdemir then turned toward the torrent carrying dozens of blocks of ice below a slope covered with grass and rocks -- a sign of glacier loss being exacerbated by global warming. "You can see that there are quite a few pieces of glacier in the water right now... the reason why the waterfalls flow lushly actually shows us how fast the ice is melting," he said. The glaciers of Mount Cilo, which rises to 4,135 meters in the province of Hakkari on the Iraqi border, are the second largest in the country behind those of Mount Ararat (5,137 meters ) -- 250 kilometres (155 miles) further north. As global temperatures rise amid human-caused climate change, new sections of the mountains that were once capped in ice are melting fast year after year. Turkey, which is experiencing heatwaves and drought, even registered a record temperature of 50.5C on Friday in Silopi, some 200 kilometres (120 miles) from Hakkari. "The melting process is faster than we expected. According to our research, in the last 40 years, we lost almost 50 percent of this continuous snow and ice cover in this place," said Onur Satir, a professor at Yuzuncu Yil University and specialist in geographical information systems in the eastern province of Van. -'No way to cover the ice'- "Some places melt faster than other places, so actually it's showing us which places must be protected but we have no opportunity to cover the whole ice area," Satir said. In recent years, several glaciers in the Alps have been covered with white tarpaulins in an attempt to delay their demise. According to the United Nations, glaciers in several regions of the world will not survive the 21st century, threatening the water supply of hundreds of millions of people. The surrounding landscape is a delight for hikers, many of whom have flocked to the Hakkari mountains since the guns fell silent in recent years in the region, where fighters from the Kurdistan Workers' Party (PKK) have long challenged the Turkish state. The ongoing peace process with the PKK listed as a terror group by Turkey and its Western allies suggests that tourism will accelerate in the area, which became a national park in 2020. -'Don't walk on the ice'- But melting ice has made certain areas dangerous. In July 2023, two hikers were killed when they were swept away by a block that broke off from a glacier. "People should not walk on the ice," Ozdemir warned, voicing concerns about the safety of hikers and the preservation of glaciers. "This region is 40-50 kilometres away from the city, but there was no road in the past. Now, with the construction of the road, more vehicles are coming here and the increase in the number of people coming here actually accelerates the melting a little bit," said the 38-year-old guide. A UN report on desertification worldwide estimates that 88 percent of Turkey's territory is at risk: rainfall is expected to decrease by 30 percent by the end of the century, while temperatures are expected to rise by 5 to 6C compared to the averages recorded between 1961 and 1990. ii-rba/fo/giv

DOWNLOAD THE APP

Get Started Now: Download the App

Ready to dive into a world of global content with local flavor? Download Daily8 app today from your preferred app store and start exploring.
app-storeplay-store