New high-resolution simulations suggest that while the frequency of severe hailstorms could drop across most of Europe by 2100, southern and Mediterranean regions may face a rise in the largest, most damaging hailstones.
Severe hailstorms cause major and costly damage to agriculture, property, and infrastructure. A new study in Nature Communications suggests that by 2100, Europe may see fewer severe hailstorms overall, but a growing risk of the most extreme hail in the south.
Researchers used convection-permitting climate models – high-resolution simulations, detailed enough to capture thunderstorms – to ask how hail potential might change in Europe as the climate warms.
The team, led by the Tyndall Centre’s Dr Abdullah Kahraman and Prof. Hayley Fowler, focused on the high-emissions RCP8.5 scenario. This pathway, often used in climate science, assumes greenhouse gases continue to rise strongly, potentially leading to more than 5°C of global warming above pre-industrial levels by 2100.
They found that while the Severe Hail Potential (SHP) could fall by over 50 per cent in summer across much of Europe, the Significant Severe Hail Potential (SSHP) – representing the top 3 per cent of hail-favourable environments – is projected to increase in southern and Mediterranean regions in autumn and winter.
Why fewer hailstorms?
Several processes in a warmer climate combine to reduce hail formation:
- The freezing level (altitude where air reaches 0°C) rises, so hailstones melt more before reaching the ground.
- Updrafts in the key hail growth zone (-10°C to -30°C) weaken, giving hailstones less time to grow.
- Wind shear (differences in wind with height) lessens, making storms less organised.
Together, these changes explain the widespread decline in hail potential across central and northern Europe.
The southern exception: “warm-type” storms
In southern Europe, however, a different pattern emerges: “warm-type” storms may become more common. These are thunderstorm environments with higher freezing levels (above ~4.5km) and characteristics more typical of subtropical or tropical systems.
Such storms favour the uplift and moisture needed to generate very large hailstones. Despite falling through warmer air, these stones may survive the fall to the ground because of their greater size.
In these regions, the risk is not disappearing but shifting – with fewer hailstones overall, but a heightened chance of the most destructive events.
Need for research and preparedness
These findings challenge earlier studies based on coarser climate models, which often suggested hail frequency would increase as the climate warms.
However, the authors stress important limits: the analysis relies on a single model run and one emissions pathway. More simulations are needed to confirm the “warm-type” hail signal, and uncertainties remain around processes such as melting at higher freezing levels.
Even so, the study highlights a key message: while much of Europe may face fewer severe hail events, southern regions could see a growing risk of rarer but far more damaging hailstorms – a challenge for insurers, farmers, and policymakers alike.
