Study shows climate change intensifying Europe's largest hailstorms
A new study reveals that climate change is making Europe's biggest hailstorms more severe, with larger hailstones forming due to warmer temperatures. Researchers analyzed data from the record-breaking 2023 hailstorm in northern Italy, where hail up to 15 centimeters fell. The findings highlight how rising atmospheric moisture is fueling these extreme weather events.
In August 2023, the village of Vivaro in northern Italy experienced one of Europe's most intense hailstorms on record. Hailstones measuring up to 15 centimeters in diameter—larger than tennis balls—rained down, causing significant damage to homes, vehicles, and crops. This event, documented in a study published in Nature Climate Change, serves as a stark example of how climate change is supercharging hail formation across the continent.
The research, led by scientists from the University of Zurich and the Institute for Atmospheric and Climate Science in Switzerland, examined hail events in Europe over the past four decades. They found that the largest hailstones have increased in size by about 10% since the 1980s. 'Our analysis shows that climate change has already made the biggest hailstorms in Europe more intense,' said lead author Maria Elison, a researcher at the University of Zurich. The study attributes this trend to higher temperatures, which allow the atmosphere to hold more moisture—up to 7% more per degree of warming, as per the Clausius-Clapeyron relation.
Hail forms when strong updrafts in thunderstorms carry water droplets high into the freezing atmosphere, where they accumulate layers of ice. In a warmer climate, these updrafts can be more powerful, and the increased moisture provides more material for hail growth. The Vivaro storm, which occurred on August 24, 2023, produced hail that weighed up to 1 kilogram each, according to eyewitness reports and meteorological data. Local authorities reported damages exceeding €10 million, including shattered roofs and flooded fields.
The study also analyzed other major European hail events, such as those in Germany and France in recent years, confirming a pattern of escalating severity in Central and Southern Europe. While smaller hail events may not show clear trends, the extremes are becoming more frequent and destructive. 'This is a wake-up call for insurance providers and urban planners,' Elison added, emphasizing the need for better preparedness.
Broader context underscores the implications: Europe's hail-prone regions, particularly the Alps and Po Valley, are warming faster than the global average. The research draws on radar data, weather models, and historical records to isolate climate signals from natural variability. No single storm can be solely attributed to climate change, but the study uses attribution science to quantify how human-induced warming makes such events more likely—by up to 20% for the largest hail in some scenarios.
As Europe faces more volatile weather, the findings urge stronger mitigation efforts to curb greenhouse gas emissions. Policymakers and communities in hail-vulnerable areas may need to invest in resilient infrastructure, from hail-resistant roofing to advanced early-warning systems.