Waves nearly 8 meters high. Spray, after crashing against the cliffs, exceeded 20 meters in height . Stretches of coast were flooded for kilometers . The storm's seismic force index was 0.31 m²/s , more than four times the average for other Mediterranean cyclones.

This is a snapshot of Sardinia hit by Cyclone Harry , which between January 19 and 22, 2026, lashed Sicily and Calabria in addition to the island. The study , "Unprecedented storm impact in the Mediterranean revealed by models and seismic noise during Cyclone Harry," was published in Communications Earth & Environment, a journal of the Nature group.

The research, coordinated by Giovanni Scicchitano (University of Bari Aldo Moro) and Andrea Cannata (University of Catania), was conducted with contributions from scholars at the INGV, CNR, the University of Palermo and Malta, ISPRA, Colorado State University, and the Royal Observatory of Belgium. It contains revealing data on the cyclone's "unprecedented" effects on the island. Like the waves: off Cagliari, the buoy recorded a significant maximum wave height of 7.8 meters. The all-time record, however, was set in the Strait of Sicily, where Harry generated the highest single wave ever documented in the Mediterranean: 16.6 meters, surpassing the previous record of 14.2 meters, recorded in Spain during Storm Gloria in 2020.

Returning to Sardinia, during those days, the Teulada-Zafferano cliffs, which are between 30 and 80 meters high, experienced spray exceeding 20 meters in height. Overall, however, wave activity in Sardinia was lower than in the Ionian Sea and Calabria. Yet, according to the researchers' simulations, Sardinia had the highest flooded surface area of all the areas analyzed (Sardinia, southeastern Sicily, eastern Calabria, and Malta): 10.22 square kilometers. The reason, they emphasize, is the vulnerability of low-lying coastal barriers.

At Poetto, for example, the reconstructed model indicates that after about two hours the waves began to overflow the lowest points of the berm (the "cord" of sand accumulated by the sea that acts as a natural embankment to the beach), which was between 2.5 and 3.2 meters high. And that after about five hours the flooding was continuous and 2.5 kilometers long, with about 0.8 meters of water along the seafront and up to 150 meters of penetration into the urban area . Furthermore, the flooded areas in the Poetto system amounted to 4.92 square kilometers .

In Colostrai , according to the simulations, 61% of the analyzed area ended up under water, the highest percentage of all the sites considered in the study.

Then, on January 19th, rainfall peaked at 30 mm/h . According to simulations, water levels reached 2 meters in Colostrai and Teulada and up to 3 meters in the back-dune area.

Finally, the storm's seismic strength index. It's not an earthquake: the researchers used seismometers as sea sensors , because high waves produce background seismic noise, a microseism. And the median value calculated during Harry by seismic stations in the Mediterranean was 0.31 m²/s, more than four times higher than the average for other cyclones compared.

After presenting the numbers, which combine satellite data, buoy and tide gauge observations, topographic and bathymetric surveys, site inspections, and high-resolution simulations, the authors draw some conclusions, which can also be useful for strengthening predictions.

On the climate front, it is emphasized that cyclones like Harry are now up to 15% windier than in the past, while the Mediterranean is warming approximately 20% faster than the planet. The authors believe this favors more frequent and powerful cyclones, capable of severely impacting even the coasts.

For this reason, the study argues, defining "generic danger zones" is no longer sufficient for prevention: local geomorphological factors are still poorly explored in risk assessments. A new vulnerability mapping is therefore needed that also considers submarine canyons, paleochannels, incised valleys, and urban fabric. This is because "future coastal planning must move beyond the concept of generic danger zones, taking into account local geomorphological complexity, which determines where, how, and with what intensity extreme marine events will affect Mediterranean coastal communities in a changing climate."

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