In a groundbreaking global climatological study, researchers have unveiled a comprehensive reconstruction of the occurrence of very large hail (VLH) events spanning 74 years, from 1950 to 2023. Utilizing an advanced additive logistic regression model known as AR-CHaMo, the team integrated valuable datasets—lightning observations, hail reports, and atmospheric predictors sourced from ERA5 reanalysis—to chart the temporal and spatial patterns of these destructive meteorological phenomena across continents including Europe, North America, and Australia. This novel approach not only quantifies VLH incidence with unprecedented clarity but also elucidates its nuanced regional behaviors, which vary strikingly according to localized atmospheric conditions and broader climatic influences.
The researchers’ model reveals that VLH occurrences are disproportionately concentrated in certain geographic hotspots. Notably, northern Argentina and the border regions where Uruguay, Paraguay, and Brazil converge see the highest frequency of these severe hail events. Similarly elevated frequencies emerge in the Great Plains of the United States and select areas of South Africa, highlighting these regions as recurrent battlegrounds for some of the planet’s most violent hailstorms. These findings align well with existing regional climatologies, reinforcing the reliability of AR-CHaMo’s predictive power. Even in areas where VLH incidence is comparatively lower—such as across various parts of Europe, Africa, Oceania, and Asia—the model successfully mirrors not only the spatial distributions but also seasonal patterns, underscoring its broad applicability.
Particularly noteworthy is the model’s ability to capture recent spikes in hailstorm activity, with 2023 marked as an extraordinary year distinguished by the highest frequency of VLH on record. This surge resonates with anecdotal reports and observational data describing an unprecedented hail season, especially in the United States and Europe. By adequately representing this extremity, the model provides a potent tool for understanding the variability and evolution of violent hail phenomena under current global climatic conditions. Such temporal fidelity strengthens the model’s utility for both scientific inquiry and practical forecasting.
One of the pivotal outcomes of the study is the identification of significant regional trends correlating VLH frequency with the broader context of global warming, though the relationship is far from uniform across the globe. Europe emerges as the most prominent case where increasing hail activity tightly correlates with rising temperatures. Northern Italy exemplifies this pattern, where enhanced low-level moisture and atmospheric instability—predominantly during the cold phase of storm systems—have driven a notable uptick in VLH occurrences. These findings emphasize how localized climate dynamics, modulated by global warming, can amplify extreme weather hazards in specific areas, posing escalating threats to life and infrastructure.
Beyond Europe, several other regions show statistically significant positive trends in VLH frequency, including the Middle East, southern Canada, various parts of Mexico, and select localized zones within the United States. This suggests that warming-related alterations in atmospheric moisture and instability parameters are contributing to heightened storm intensity and hail sizes in multiple northern hemisphere regions. However, the researchers caution that increases in temperature alone do not explain elevated hail hazards everywhere, indicating that other meteorological factors must also be considered to accurately assess future hail risk.
A compelling counterpoint is presented by regions where VLH occurrence is declining, despite warming trends. For example, the western United States and large swaths of continental Australia experience decreased hailstorm potential attributable to atmospheric drying. Diminished moisture availability depresses convective storm development and consequently lowers VLH frequency in these areas. Meanwhile, the Southern Hemisphere observes the most pronounced negative trends predominantly in South Africa and northern Argentina. Here, decreasing mid-level humidity and instability drive reduced hail activity, illustrating the complex interplay of atmospheric variables that govern storm dynamics globally.
The intersection of VLH frequency changes and the resulting economic impacts forms another critical dimension of the research. The study examined trends in hail-related economic losses, uncovering that parts of Europe, the United States, and Australia have all experienced increases in such loss events. In Europe, a direct connection between rising VLH occurrences and greater economic damage emerges. This pattern likely reflects not just the increased frequency and severity of hailstorms but also heightened societal exposure and vulnerability in affected areas. Consequently, risk mitigation strategies in these regions must incorporate both meteorological forecasting and adaptive infrastructure planning.
Contrastingly, in the United States and Australia, the study found no clear meteorological correlation with increased hail loss events. Instead, the rise in economic damage is primarily driven by factors unrelated to the frequency or intensity of VLH, such as growing urbanization and greater asset values in vulnerable regions. This distinction underscores the critical importance of “loss normalization” practices, which adjust damage assessments for changes in exposure and vulnerability over time. Future research efforts emphasizing more granular analyses of these socioeconomic drivers are essential for disentangling climate-related effects from socio-economic growth patterns in hail damage statistics.
Despite its important contributions, the study highlights several limitations that must temper the interpretation of its findings. The AR-CHaMo model, trained primarily on data from mid-latitude regions of Europe, the USA, and Australia, was applied globally, thereby inviting caution for its outputs in regions where hail climatologies differ substantially or where the ERA5 reanalysis dataset is known to possess biases—particularly in tropical zones. Addressing these regional data gaps represents a promising avenue for improving VLH modeling globally. Incorporating emerging hail observation databases from South America, Canada, and China will help refine the model’s capabilities in capturing hailstorm environments across diverse climatic contexts.
Another recognized limitation concerns the spatial resolution of the ERA5 reanalysis data. The current temporal and spatial granularity constrains the ability to explicitly simulate detailed storm development processes responsible for VLH formation. Advances in high-resolution reanalysis products, or the integration of convection-resolving numerical weather prediction models, could significantly enhance future VLH reconstructions. Such improvements would allow for a more mechanistic understanding of hailstorm genesis and evolution in varied atmospheric settings.
Ultimately, this research offers a robust and comprehensive climatological portrait of very large hail occurrence worldwide, mapped over an unprecedented timeframe. It reveals the intricate variability of VLH patterns and trends in the context of a changing climate, while also connecting these physical phenomena to their tangible societal impacts through economic loss analysis. Its findings serve as a clarion call for enhanced observation networks, refined modeling techniques, and targeted adaptation strategies to mitigate the risks posed by these extreme weather events.
The study’s revelations have profound implications for efforts aimed at managing hail-related hazards, from improving severe weather warnings to informing urban planning and agricultural insurance schemes. Policymakers and practitioners alike stand to benefit from its detailed evidence of where and how VLH risks are intensifying or receding and the underlying meteorological and socioeconomic factors at play. The differentiated regional responses to warming revealed by this research stress the need for nuanced and context-specific approaches to disaster risk reduction.
As the climate crisis continues to reshape atmospheric dynamics globally, understanding the evolving behavior of hailstorms—some of the most destructive convective phenomena—remains a critical scientific and societal challenge. This study lays a rigorous foundation for continued exploration and improved forecasting of VLH events, leveraging state-of-the-art statistical modeling and reanalysis datasets. By bridging physical climatology with economic impact assessments, the research advances the frontier of knowledge on how severe storms intersect with human vulnerabilities in a warming world.
Future directions must prioritize integrating diverse observational datasets and refining computational models to capture the full complexity of hailstorm climatology across all latitudes. Doing so will enhance predictive accuracy and contribute to developing resilient infrastructure and insurance systems that can withstand the increasing volatility of extreme weather. In this regard, the findings presented here represent both a milestone achievement and a starting point for ongoing scientific innovation and societal preparedness efforts against the intensifying peril of very large hail.
The sophisticated use of additive logistic regression to combine multiple data streams—lightning, hail reports, and meteorological reanalysis—exemplifies the power of interdisciplinary approaches to unravel the complexity of natural hazards. This innovative methodology enables researchers to fill observational gaps and extend threat assessments beyond observational strongholds to a truly global scale. Such integrative frameworks are increasingly vital in the era of climate change, where localized impacts are inherently linked to planetary scale transformations.
As extreme weather events attract growing public and scientific attention, this study’s granular benchmark for VLH phenomena highlights the necessity of sustained investment in monitoring, modeling, and risk communication. The ability to project future hailstorm behavior under different climate scenarios, and to parse out the contributions of meteorological versus socio-economic changes, will be critical for crafting effective vulnerability reduction and climate adaptation policies. The insights offered herein illuminate a path toward safer, better-informed communities poised to confront the enduring challenge of hail in a warming world.
Subject of Research: Global climatological trends of very large hail (VLH) events and associated economic losses under changing climatic conditions.
Article Title: Contrasting trends in very large hail events and related economic losses across the globe.
Article References:
Battaglioli, F., Taszarek, M., Groenemeijer, P. et al. Contrasting trends in very large hail events and related economic losses across the globe. Nat. Geosci. (2025). https://doi.org/10.1038/s41561-025-01868-0
Image Credits: AI Generated
