Hurricane classification has long relied on the Saffir-Simpson Hurricane Wind Scale (SSHWS), a system originating in the 1970s that simplifies a storm’s potential impact solely through wind speed measurements. However, new interdisciplinary research spearheaded by Jennifer Collins, a geosciences professor at the University of South Florida, challenges this long-standing paradigm. Collins and her colleagues argue that current hurricane categorization dangerously underrepresents the real threats posed by these destructive weather systems by excluding storm surge and rainfall—two factors responsible for the majority of hurricane-related fatalities. Their groundbreaking work introduces a more holistic approach, the Tropical Cyclone Severity Scale (TCSS), designed to revolutionize how hurricanes are communicated and understood by the public.
Traditional evaluations of hurricanes have primarily focused on maximum sustained wind speeds to assign categories ranging from 1 to 5. This singular metric, while intuitive, neglects other deadly components such as inundation caused by storm surge and inland flooding from heavy precipitation. Historical hurricanes like Katrina in 2005 and Florence in 2018 have exemplified this oversight. Katrina, rated as a Category 3 at landfall, inflicted most of its devastating damage and loss of life through storm surge and rainfall rather than wind. Likewise, Florence, a Category 1 storm, led to catastrophic flooding that claimed dozens of lives. Collins’ research stresses that these examples are not anomalies but symptomatic of a systemic flaw in risk communication to vulnerable populations.
Underpinning this reform is a quantitative reinterpretation of hurricane hazards backed by decades of data. A pivotal 2014 study by Edward Rappaport, formerly of the National Hurricane Center, quantified wind as responsible for a mere 8% of hurricane fatalities, while storm surge accounted for nearly half, and rainfall contributed to over a quarter. These findings emphasize the necessity for a multi-hazard perspective in evaluating tropical cyclone risks. By integrating multiple dimensions of hazard severity, the TCSS aims to represent the composite dangers that each hurricane poses, transcending the narrow wind-only framework that has dominated forecasting for the past half-century.
The innovative TCSS assigns hazard-specific ratings from 1 to 5 to wind, rainfall, and storm surge based on their predicted intensities. What distinguishes this new scale is its ability to amalgamate these three components into a composite category that may rise to a maximum of 6, thus communicating compounded risks when more than one hazard reaches elevated levels. For instance, if one hazard rates significantly higher than the others, the scale reflects that severity directly. Additionally, when multiple hazards exceed Category 3 thresholds, the final rating is incremented, reflecting the synergistic amplification of risk from concurrent extreme events. This nuanced scoring mechanism supplies a more accurate representation of potential impacts, allowing emergency managers and the public to grasp the multidimensional threat landscape.
To ascertain the real-world effectiveness of the TCSS, Collins and her interdisciplinary team conducted a large-scale online experiment involving 4,000 residents vulnerable to hurricane threats along the Gulf and East coasts of the United States. The participants received simulated forecasts for ten fictional hurricanes, split into two groups: one exposed to the conventional SSHWS warnings and another to the enhanced TCSS system. The experimental design meticulously assessed participants’ abilities to identify the primary hazard, their perceived risk of remaining at home, and their evacuation intentions. This empirical approach marks a significant step toward evidence-based improvements in hurricane communication and public safety protocols.
Results from the study illuminated the tangible benefits of multi-hazard communication. Those informed through the TCSS framework demonstrated a markedly higher accuracy in identifying the main threat—be it wind, rain, or storm surge—compared to recipients of traditional SSHWS warnings. More critically, the likelihood of evacuation increased substantially for storms where flood and surge hazards dominated but were previously underemphasized. Collins underscores that many individuals anchor their evacuation decisions primarily to category number rather than nuanced hazard information. Therefore, by adjusting categories to reflect the combined severity of multiple hazards, the TCSS enhances the motivational clarity behind evacuation advisories, potentially reducing preventable loss of life.
The development of the TCSS reflects a promising shift toward integrating meteorological science with behavioral research on risk perception. Hurricanes are dynamic systems producing varied and localized hazards, yet public messaging has remained static for decades. The interdisciplinary collaboration—spanning USF, the University of Amsterdam, and Tilburg University—exemplifies this holistic vision. Co-authors Nadia Bloemendaal, Jantse Mol, Hans de, and Dianna Amasino contributed expertise in evacuation behavior, atmospheric sciences, and risk communication, culminating in a scientifically robust scale published initially in 2021 and now rigorously evaluated for practical deployment.
Adopting the TCSS will require institutions to confront organizational inertia since the SSHWS has been deeply entrenched in official discourse and media representation since 1971. Despite modifications in 2012 that narrowed SSHWS to wind-speed analysis, the original scale’s legacy endures in public consciousness and emergency management policies. Yet, Collins’ optimism stems from the compelling evidence revealed by empirical testing that people respond more rationally to multi-hazard information. Improved public comprehension translates directly into enhanced preparedness and survival outcomes, making a compelling case for the National Hurricane Center and other agencies to embrace this paradigm shift.
Technically, the application of the TCSS demands advances in forecasting models that can accurately predict and integrate storm surge, precipitation, and wind intensity in real-time. This integration involves sophisticated hydrodynamic and atmospheric simulations requiring high-resolution data inputs and robust computational frameworks. As weather monitoring technology evolves, these predictions become increasingly precise, paving the way for operationalization of the TCSS. Moreover, effective dissemination channels—ranging from traditional media to mobile alerts and social platforms—will be critical in translating complex hazard information into actionable public advisories.
Beyond scientific and technical considerations, the TCSS initiative aligns with broader climate resilience and adaptation goals. As climate change intensifies storm characteristics, including rainfall volumes and surge potential, reliance on outdated classification systems risks underpreparing communities for escalating threats. The TCSS acknowledges this urgent reality by delivering a future-proofed framework that encapsulates multiple hazard vectors, fostering more responsive urban planning, infrastructure fortification, and emergency response strategies.
Jennifer Collins’ research journey also highlights the impact of experiential knowledge gained during recent hurricane seasons. Florida, a hotspot for tropical cyclones, provided real-time observational opportunities during hurricanes Matthew, Irma, Ian, Helene, and Milton. These events afforded critical behavioral data and contextual insights fueling iterative improvements to the TCSS and its communicative clarity. This proximity to active hurricane environments strengthens the scale’s empirical foundation and bridges the gap between theoretical modeling and lived experience.
Looking forward, the scientific community awaits the National Hurricane Center’s evaluation of the TCSS proposal. While previous attempts to overhaul hurricane scales have surfaced, none combined rigorous experimental evidence with an emphasis on public risk perception as thoroughly as this initiative. If accepted, the TCSS has the potential to redefine how millions interpret hurricane severity, transforming a traditionally one-dimensional metric into a multidimensional, life-saving communication tool.
In conclusion, Jennifer Collins and her team’s Tropical Cyclone Severity Scale represents a pivotal evolution in hurricane science and risk communication. By reflecting the complex interplay of wind, rainfall, and storm surge hazards, the TCSS addresses critical gaps in public understanding and emergency management. As climate dynamics render tropical cyclones increasingly multifaceted, this innovative scale offers a scientifically supported, behaviorally informed way forward to safeguard vulnerable communities effectively.
Subject of Research: People
Article Title: An experimental test of risk perceptions under a new hurricane classification system
News Publication Date: 19-Aug-2025
Web References:
https://www.nature.com/articles/s41598-025-14170-1
References:
Rappaport, E. (2014). Study on hurricane fatalities attribution. National Hurricane Center.
Collins, J., Bloemendaal, N., Mol, J., de H., & Amasino, D. (2025). An experimental test of risk perceptions under a new hurricane classification system. Nature Scientific Reports. DOI: 10.1038/s41598-025-14170-1
Image Credits: Jennifer Collins, University of South Florida (Credit: USF)
Keywords: Hurricanes, Climate systems, Cyclones, Weather, Storms, Wind speed, Weather forecasting, Extreme weather events, Meteorology
