Italy Under Siege: Torrential Rains Cause Catastrophic Flooding Across Regions

Northern Italy recently experienced a dramatic and sudden shift from prolonged extreme heat to a period of exceptional rainfall, widespread flooding, and a significant drop in temperatures. This severe weather disturbance primarily impacted the regions of Liguria, Lombardy, and the northern part of Tuscany, bringing widespread disruption and damage.

The root cause of this intense weather event was attributed to a marine heatwave in the Mediterranean Sea, which had pushed water temperatures off the Spanish island of Majorca above 33 degrees Celsius. When the initial flow of cooler, more unstable air encountered the hot air masses lingering over northern Italy, combined with the high humidity absorbed from the superheated sea, it triggered a series of extreme late-summer weather events.

Liguria was the first region to feel the full force of the disturbance, recording approximately 40,000 lightning strikes within 24 hours. A Frecciabianca train bound for Rome was struck, forcing it to stop and passengers to disembark. In the regional capital, Genoa, storms caused extensive damage to seaside bathing facilities, particularly between Cogoleto and Arenzano, where cabins, sunbeds, and parasols were swept away. Agriculture also suffered heavy losses, with the Coldiretti farmers' association reporting an “alarming” situation for olive growing in the Tigullio hinterland, leading to a compromised year for the olive harvest and losses in the wine-growing sector. Another lightning strike hit the railway traffic control centre at Ventimiglia station, disrupting train services. Off the Tigullio coast, a meteorological “supercell” formed, unleashing extraordinary rainfall, with 200 millimetres falling on Chiavari and Lavagna within 24 hours, and a waterspout developing off Rapallo. Numerous streets in these municipalities were flooded, damaging infrastructure and shops, while trees fell on the hills above Sestri Levante.

Northern Tuscany also endured significant impact, with over 23,000 lightning strikes recorded. The Lamma Consortium reported rainfall totals of 60–70 millimetres in Massa Carrara, Lucca, and Grosseto provinces, and 40–50 millimetres in Siena, Pisa, and Livorno within a twelve-hour period. High winds were a major factor, with gusts reaching up to 106 km/h on the Pisa coast, 103 km/h in Florence province, 93 km/h on Gorgona, 92 km/h in Viareggio, and 86 km/h in the Arezzo area. In Grosseto, a tornado caused substantial damage, ripping off the roof of a building.

In Lombardy, the provinces of Brescia, Sondrio, and Bergamo were among the worst affected. A debris flow from Val Rabbia in Sonico carried water, boulders, and rubble onto state road 42 towards the Tonale Pass, resulting in a bridge collapse. Around 350 people were evacuated in the Bergamo area due to the extreme weather. The Orobic Alps near Lake Como registered up to 250 millimetres of rainfall. Alta Val Brembana, also in Bergamo province, experienced a slope collapse along a provincial road, and falling trees damaged several parked cars. Six municipalities—Valleve, Carona, Foppolo, Branzi, Valbondione, and Gandellino—were cut off, and a campsite at Isola di Fondra was evacuated due to landslide risks.

While specific analyses are required to directly link any single weather event to global warming, scientists have consistently warned that the increase in global average temperatures, primarily driven by human activities like burning fossil fuels, will lead to a higher frequency, intensity, and duration of extreme weather phenomena. This includes not only heatwaves, droughts, and wildfires, which have recently affected regions like France and Spain, but also exceptional rainfall and flooding, as witnessed in northern Italy. Europe, in particular, appears to be experiencing climate warming at a faster rate than the global average, thereby increasing the likelihood of such severe events. According to the European climate monitoring service Copernicus, the June–July average temperature record set in 2022 was surpassed due to extreme heatwaves in western Europe, pushing the two-month average to 21.62°C.