Alps at risk: with 2°C increase, extreme summer thunderstorms double
19.06.2025
A study published in the journal «npj Climate and Atmospheric Science» by a group of researchers from the University of Padua and the University of Lausanne analysed data from nearly 300 weather stations located in the Alps. The research indicates that a 2°C increase in the region's average temperature could lead to a doubling of the frequency of extreme summer thunderstorms. Intense and short-duration rainfall, capable of releasing large amounts of rain in a few minutes or hours, can cause severe material damage and pose a risk to human lives. An example is the extreme weather event that hit the Marche region in September 2022, causing the death of 13 people and damage worth 2 billion euros due to over 100 mm of rain falling in one hour.
With global warming, these extreme events risk becoming more frequent, especially in the Alpine region, where temperatures are rising faster than the global average. Warmer air holds more moisture and intensifies thunderstorm activity. Quantifying the impact of climate change on these events is crucial.
The study, titled "A 2°C warming can double the frequency of extreme summer downpours in the Alps", used a statistical model based on physical principles to establish the link between temperature and rainfall frequency, and to simulate the future frequency of extreme precipitation using regional climate projections. The research demonstrated that an average temperature increase of 2°C could double the frequency of short-duration summer thunderstorms in the Alpine region: events that currently occur every 50 years could happen every 25 years in the future.
The researchers emphasise that even a 1°C increase could intensify problems in mountainous areas, and that this increase is not hypothetical but likely to occur in the coming decades. Currently, there is already a trend towards more intense summer thunderstorms, which is expected to worsen further. The sudden and massive influx of large volumes of water prevents the soil from absorbing the excess, triggering flash floods and debris flows, causing damage to infrastructure and, in some cases, fatalities.
The authors of the study conclude by highlighting the importance of understanding how these events will evolve with climate change in order to plan appropriate adaptation strategies, including infrastructure adjustments. With a 2°C increase in the regional average temperature, the statistics on extreme precipitation in the Alps will likely undergo significant changes, increasing the probability of extreme rainfall events. An in-depth understanding of these phenomena and timely action are essential to protect mountain communities and preserve the unique ecosystem of the Alps for future generations.
