By Euronews Green
Published on
ADVEReadNOWISEMENT
New research has revealed how climate change is intensifying supercell thunderstorms in Europe.
The study, published in Science Advances, warns that the Alpine region and parts of Central and Eastern Europe can expect a significant increase in storm activity.
If global temperatures rise by 3°C above pre-industrial levels, storm frequency on the northern side of the Alps could surge by up to 50 per cent.
These powerful storms are already among the most damaging weather events in Europe, resulting in increasing insurance loss claims in recent years. Understanding how the conditions under which they form and how our warming world is changing them is vital for preparedness, the researchers say.
What is a supercell thunderstorm?
Unlike a typical thunderstorm, a supercell has a deep, rotating column of air inside it known as a mesocyclone. This spinning updraft is what gives them their unique strength and staying power. While most thunderstorms burn out pretty quickly, supercells can last for hours and stretch across vast areas.
They form under conditions where there is warm, moist air near the ground, cooler air higher up and wind that changes direction with height. These elements make the atmosphere unstable, and it starts to spin, setting the stage for a supercell to develop.
Typically occurring in summer, supercell thunderstorms bring strong winds, very large hail and heavy rain. Despite being relatively rare in Europe, these storms account for a significant proportion of thunderstorm-related hazards and financial losses.
The rising risk of damage from supercell thunderstorms
Severe convective storms, including supercell thunderstorms, long-lived windstorms and large hail events, have resulted in increasing insurance loss claims in recent years. In 2023, severe convective storms were the world’s costliest type of natural hazard, reaching total insured losses of nearly €55 billion.
Though they are comparatively rare in Europe, accounting for just a small proportion of the continent’s thunderstorms, they can still bring severe localised damage.
In June, a supercell struck L’Hôpital-le-Grand in France’s Loire department, producing hailstones up to 6 cm in diameter, which damaged properties and vehicles.
And another powerful supercell thunderstorm hit Italy in August last week, causing widespread damage across Rimini and Ravenna. It brought intense hail, rain and winds of nearly 100 km/h, which uprooted trees, damaged vehicles and destroyed crops. Trains were disrupted when a tree fell on the Rimini Ravenna line.
How are scientists tracking Europe’s supercell thunderstorms?
Tracking supercells across Europe has historically been challenging due to inconsistencies in national weather radar systems.
Corresponding author Monika Feldmann, from the Mobiliar Lab for Natural Risks and the Oeschger Centre for Climate Change Research at the University of Bern, says this makes cross-border storm detection more difficult.
To overcome this, researchers from the University of Bern’s Mobiliar Lab for Natural Risks and the Oeschger Centre for Climate Change Research, in collaboration with ETH Zurich, developed a high-resolution simulation model.
This model uses digital mapping techniques to simulate storm cells at a very fine scale, offering a far more detailed picture of storm development than was previously possible.
The Alps are a thunderstorm ‘hotspot’
The new modelling identified the Alps as a hotspot for supercell thunderstorms. The region experiences around 38 of these power storms per season on the northern side of the mountain range and 61 on its southern slopes.
With 3°C of warming, the study predicts up to a 50 per cent increase in supercell occurrences in this mountainous region, amplifying risks for countries like Switzerland, Austria, northern Italy, and southern Germany. In contrast, the Iberian Peninsula and the southwest of France could see a decrease.
Overall, researchers estimate an 11 per cent increase in supercell thunderstorms across Europe.
“These regional differences illustrate the diverse effects of climate change in Europe,” Feldmann adds.
The study underscores the urgent need for European countries to prepare for a future with more frequent and intense severe weather events. Infrastructure, agriculture, emergency services, and insurance systems will all need to adapt.
Understanding the conditions that create these supercell storms, Feldmann says, is the key to better preparedness.