Hydrogeological instability

Landslide-prone areas increase by 15% from 2021 to 2024

This is what emerges from the fourth Dissesto idrogeologico report, prepared by Ispra. The most significant cases in the Province of Bolzano, Tuscany, Sardinia and Sicily

31 July 2025

3' min read

From the Province of Bolzano to Tuscany, via Sicily and Sardinia: the area of national territory at risk from landslides in hydrogeological planning is growing. There has been a 15% increase since 2021, as the surface area affected has risen from 55,400 thousand square kilometres in 2021 to 69,500 thousand square kilometres in 2024, "equal to 23% of the national territory".

Report details

These are just some of the elements that emerge from the fourth Ispra report on 'Hydrogeological instability' 2024 edition. The most significant increases, as underlined by Ispra, "are found in the Autonomous Province of Bolzano (+ 61.2%), Tuscany (+ 52.8%), Sardinia (+ 29.4%) and Sicily (+ 20.2%) and are mainly due to more detailed studies carried out by the District Basin Authorities and the Autonomous Provinces". Not only that, the areas classified as more dangerous (high P3 and very high P4) from 8.7% to 9.5% of the national territory. In 2024, 94.5% of Italian municipalities will be at risk of landslides, floods, coastal erosion or avalanches.

Hydro-meteorological events

"The three-year period 2022-2024 was marked by hydro-meteorological events of exceptional intensity," Ispra writes in the report: the widespread floods along the main and secondary river courses in the Marche region in September 2022, the rapid mud and debris flows on the island of Ischia in November 2022 with 12 deaths, the floods in Emilia-Romagna in May 2023, with damage estimated at €8.6 billion, and the intense rainfall in Valle d'Aosta and northern Piedmont in June 2024, with significant effects in terms of floods and debris flows."

The role of climate change

Climate change also plays a role in all this. Climate change, the Ispra experts argue, 'is causing an increase in the frequency of intense and concentrated rainfall, with a consequent increase in surface landslides, rapid mud and debris flows, and floods, including flash floods, amplifying the risk with impacts even on historically less exposed territories'.

Landslide Emergency

Over 636,000 landslide phenomena have been registered in the national panorama. It is, as the report states, "one of the most exposed countries in Europe". The data are contained in the Inventory of Landslide Phenomena in Italy, produced by Ispra in collaboration with the Regions, Autonomous Provinces and Regional Agencies for Environmental Protection (Arpa). "This is an important figure, if we consider that about 28% of these phenomena," the experts go on to argue, "are characterised by extremely rapid dynamics and high destructive potential, with often dramatic consequences, including the loss of human lives.

5.7 million inhabitants in landslide-prone areas

In 2024, the population at risk of landslides in Italy is 5.7 million inhabitants. Of these 1.28 million inhabitants reside in areas with a higher hazard level (P3 and P4), equal to 2.2 per cent of the total population. Not only that, more than 582 thousand families, 742 thousand buildings, almost 75 thousand local business units, and 14 thousand cultural assets are exposed to risk in areas of greater landslide hazard.

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Improving beach situation

Within this framework, the situation of Italian beaches is improving: on the coastal erosion front, more stretches are advancing, with + 30 kilometres, than are being eroded.

"More than 1,890,000 kilometres of beaches have undergone significant changes between 2006 and 2020, with shoreline alterations of more than 5 m, equal to about 23% of the entire Italian coastline, or 56% of beaches alone, with 965 kilometres that are advancing and 934 kilometres that are eroding," the report continues. "This indicates a reversal of course and a prevalence of the length of the advancing stretches of coastline over the eroding ones of about 30 kilometres.

13% of mountain territory at risk of avalanche

On the avalanche front, the surface area potentially subject to avalanche phenomena is 9.283 thousand square kilometres, or 13.8 per cent of the mountainous territory above 800 metres above sea level.