Large hailstones: incidents up by 80% in Italia

“In general,” Radarmeteo-Hypermeteo adds, “a warmer-than-average Mediterranean Sea can be a contributing factor to more intense thunderstorms, as it increases the amount of heat and moisture available in the lower layers of the atmosphere. At present, sea surface temperatures are above the climatic average, with some significant anomalies: this may help to fuel more humid and potentially more unstable air masses, thereby amplifying the intensity of the thunderstorms.”

That’s not all. Urban sprawl and the urban heat island effect can also play a role. “Artificial surfaces accumulate more heat than rural or vegetated areas,” they continue, “thereby warming the layer of air near the ground more; this can accentuate the vertical temperature gradient and encourage updrafts, creating conditions more conducive to the formation or intensification of thunderstorm cells, especially in areas that are already unstable.”

According to the European Environment Agency, Italia is among the EU countries suffering the greatest economic losses as a result of climate-related events, which are increasing in both frequency and severity. In recent years, extreme weather events have increased sharply, and the period 2022–2024 is one of those in which the greatest damage has been recorded, with an exponential rise in the number of such events.

Another factor triggering extreme weather events is the gradual replacement of the Azores High by the African High, which is more intense and humid. ‘This situation,’ continue Radameteo-Hypermeteo, ‘leads to a general increase in the frequency of heatwaves, droughts and severe weather events such as heavy thunderstorms, with an increase in hailstorms both in terms of frequency and diameter, particularly in the northern parts of the country; during the summer months, the highest risk of hailstorms is recorded between June and July, whilst in August there is generally a decline.”

In terms of hail, the three-year period 2021–2023 was the most active on record: on 24 July 2023, severe thunderstorms caused hailstorms with hailstones up to 19 centimetres in diameter in Azzano Decimo (Pordenone), which remains a European record.

Various insurance reports (Swiss Re, Munich Re, etc.) identify hail as one of the fastest-growing secondary risks, and Italia is one of the countries most at risk due to its climatic conditions and topography. This is also reflected in a sharp rise in motor insurance claims resulting from weather events, year on year: in July 2023, damage totalling around 4 billion was caused by episodes of intense hailstorms occurring over the space of a few days, leading to difficulties in managing the peak in claims and a consequent review of insurance premiums by geographical area.

And hailstorms are expected to become even more frequent in the future

‘Looking to the future,’ the climate analysis centre concludes, ‘some studies show that, under current scenarios of global temperature rise, severe events such as those currently being recorded could increase by between 50 per cent and over 100 per cent by 2100.’