This week, Europe has been gripped by a brutal wave of severe weather. From central France to northern Italy, a series of violent storms unleashed torrential downpours, fierce winds, and hailstones rivaling tennis balls in size.
Supercell Outbreak in Central France
The departments of Loire and Puy‑de‑Dôme in central France were among the hardest hit. Supercell thunderstorms brought relentless rain, intense wind gusts, and hailstones reaching up to 6 cm (2½ in) in diameter—larger than ping-pong balls. The storms triggered flash floods, infrastructure damage, and even a brief, localized mini‑tornado.
⛈️ Une nouvelle supercellule a été détectée sur les mêmes secteurs qu’il y a deux jours. Les monts et les plaines du #Forez, dans la #Loire, sont actuellement touchés par d’importantes chutes de #grêle, parfois supérieures à 4 cm de diamètre. Des dégâts ont déjà été signalés… pic.twitter.com/LeO7jabxO0
— vigiprevention_meteo (@VigipreventionM) June 3, 2025
Meteorologists attribute this to warm, moisture-laden Mediterranean air colliding with cooler northern currents. Mountain ranges such as the Vosges and Jura amplified the storms through orographic uplift. Elevated wind shear further helped form rotating updrafts, delivering some of the largest hailstones recorded this season.
This event followed what local media described as a “mini-tornado” and hailstorms in the Loire department on June 1.
@KeraunosObs confirme le passage d'une #tornade dans la #Loire dimanche 1er juin.
— France 3 Rhône-Alpes (@F3Rhone_Alpes) June 3, 2025
Le phénomène météorologique a ravagé plusieurs communes, décrochant des toitures et laissant les rues remplies de débris. https://t.co/W3qu7egrSF pic.twitter.com/863mzHl2i3
Warnings Across the Channel
The UK’s Met Office issued a yellow thunderstorm warning for central and southern England and Wales, valid from Saturday morning to early evening. The risks included 40 mm (1.6 in) of rain in just a few hours, sudden wind bursts, hail, and frequent lightning bolts.
Chief Meteorologist Dan Suri likened forecasting such storms to predicting where bubbles form in a boiling pot—small, fast-developing, and unpredictable.
Violent Weather in Germany, Austria, and Czechia
Lightning played a dangerous role this week. France logged around 70,000 thunderclaps in the Pas‑de‑Calais alone, leading to strikes that knocked out power to over 11,000 homes. Germany’s Hamburg saw roofs ripped off, flooded basements, and uprooted trees—all of which required a mobilization of 1,000 emergency responders.
Slovenia’s Hail Alley
On June 3, a supercell thunderstorm struck the Goričko region in northeastern Slovenia—often referred to as Europe’s “hail alley”—bringing hailstones larger than tennis balls (6–7 cm / about 2.4–2.8 inches) to the towns of Lucova, Šulinci, and Gornji Petrovci.
According to ARSO, nearly every roof in the area sustained damage. Skylights at a local school were shattered, and crops were flattened by the storm. Village crews used backhoes to clear piles of hail, while one mayor appealed for assistance to protect vulnerable orchards. Downed trees and ruptured drainage systems overwhelmed emergency responders, with full recovery expected to take several days.
Very large hail (up to 6-7 cm) on this supercell as it crossed NE Slovenia. Big time damage reported.
— Jure Atanackov (@JAtanackov) June 4, 2025
Slovenia is part of what might be called Europe's hail alley: the south edge of the Alps – north Italy, Slovenia, south Austria, possibly also the eastern edge of the… https://t.co/pAgXWbCDcL pic.twitter.com/3SFi1HmIwD
Hungary & Czechia
Hungary faced similar severe weather on June 3, as two powerful supercell storms moved in from the west, unleashing intense conditions primarily across Western Transdanubia.
The storms first hit the regions of Szentgotthárd and Körmend, then intensified along the Tapolca line. Hailstones larger than walnuts (over 4 cm / ~1.6 inches) damaged trees, vegetable gardens, and farmland, while roads were blanketed with fallen leaves and debris.
This prompted a second-level storm warning for Lake Balaton’s central and western basins, where swimming was prohibited due to hazardous conditions.
Yesterday's supercell over Lake Balaton was such a monster, seems like the summer season is officially ON here in Hungary pic.twitter.com/3hiJYP7RkC
— Joe (@huahinjoe) June 4, 2025
On June 3, the town of Rokycany in western Bohemia, Czech Republic, was hit by flash floods following intense convective rainfall, as predicted by the Czech Hydrometeorological Institute.
Overflowing waterways inundated streets and basements, triggering a state of emergency. Firefighters evacuated elderly residents and worked to pump water from homes, while assistance arrived from Pilsen and Prague to support displaced families. Sandbags were deployed in an effort to prevent further flooding.
Climate Context and Future Trends
Emerging studies indicate that while supercells were rare in Europe historically, roughly 700 occur each convective season today—especially around mountainous areas like the Alps . Advanced climate models suggest their frequency may rise by about 11 % if the climate warms by approximately 3 °C, potentially leading to even more frequent intense hailstorms in central and eastern Europe.
Although no widespread fatalities have been reported, significant injuries, structural damage, and transportation disruptions have been tallied across nations. Early damage estimates from last night’s storms exceed €3.6 billion in Germany alone—making it one of the country’s costliest thunderstorm episodes to date.
What the Coming Days May Bring
• France & Germany: Expect continued unsettled conditions. Lightning storms may persist, especially near mountains. • UK & Ireland: A mix of clearing spells and lingering showers—occasional heavy bursts remain possible until later this weekend. • Central/Eastern Europe: Thunderstorm risk remains elevated, especially in or near alpine foothills.
Despite the temporary drop in temperatures, the storm cycle is likely to continue as the atmosphere stays unstable. Experts are urging residents to stay alert for flood watches, lightning, and hail advisories in the days ahead.
