Greek-Albanian floods on 18-21 November 2025 likely intensified by climate change

Contact Authors

• Stavros Dafis, National Observatory of Athens, Institute of Environmental Research and Sustainable Development & Climatebook  📨sdafis@noa.gr 🗣️ Greek, English

• Konstantinos Lagouvardos, National Observatory of Athens, Institute of Environmental Research and Sustainable Development & Climatebook 📨lagouvar@noa.gr 🗣️ Greek, English, French

• Davide Faranda, IPSL-CNRS, France  📨davide.faranda@lsce.ipsl.fr 🗣️English, French, Italian

Citation

• Dafis, S., Lagouvardos, K., & Faranda, D. (2025). Greek-Albanian floods on 18-21 November 2025 likely intensified by climate change. ClimaMeter, Institut Pierre Simon Laplace, CNRS. https://doi.org/10.5281/zenodo.17748567

Press Summary

• Storms similar to the Mediterranean Depression on 18-21/11 are up to 0.5 hP deeper, up to 4 km/h windier over the Southern Ionian Sea, and up to 2 mm/day wetter in the present than they would have been in the past.

• Greek-Albanian floods were driven by rare meteorological conditions.

• Natural variability alone cannot explain the increase in rain and wind linked to the severe weather events in Greece and Albania on 18-21/11.

Event Description

Between 18 and 21 November 2025, a slow‑moving low‑pressure system affected the Ionian Sea and the Balkans. A persistent south‑westerly flow transported very moist air from the central Mediterranean towards Western Greece and Albania. When this air mass encountered the steep orography of the Pindus mountain range, rainfall was strongly enhanced, leading to prolonged periods of heavy precipitation over the regions of Epirus and Western Sterea in Greece, as well as parts of southern Albania.

Over 4 days, accumulations of rain led to rapidly rising river levels, flash floods and landslides. Urban areas such as Ioannina, Durrës and Tirana experienced flooding of streets and underpasses, overflow of small streams and significant disruption to transport. Agricultural land in low‑lying valleys near the Ionian coast was inundated, and damage to local infrastructure, including roads and bridges, was reported. The most high-impact event took place on 21 November, when a low-level convergence zone over a highly unstable air mass in Western Greece provided favorable conditions for training convection and very high rain rates. Up to 326 mm of daily accumulated rainfall was reported by a weather station in Pramanta, Greece and 7 more stations reported more than 200 mm in less than 24 hours and up to 483 mm in 4 days in Epirus, Greece. 

The combination of persistent heavy rainfall, saturated catchments and complex terrain meant that even locations away from major rivers were exposed to surface‑water and flash flooding. 

The Surface Pressure Anomalies reveal a large negative (cyclonic) anomaly over Italy and Adriatic Sea with values up to -6 hPA. In the context of Mediterranean extratropical storms, this setup can be associated with extensive precipitation and intense wind due to the deepening pressure gradient. Temperature Anomalies show temperatures up to 1.5 °C warmer than average over the Central Mediterranean, affected by the warm sector of the cyclone. Precipitation Data show intense daily precipitation (up to 50 mm/day) over Greece and Albania. Windspeed data show large areas over Greece affected by sustained winds between 30 km/h and 50 km/h.

Climate and Data Background for the Analysis

The IPCC AR6 Chapter 11 states that climate change affects storminess in Europe, with negative repercussions that are exacerbated by rising sea levels and heavy precipitation. From a global warming level of 2 °C or higher a slightly increased frequency and amplitude of extratropical cyclones, strong winds and extratropical storms is projected for the Mediterranean Sea with medium confidence (IPCC AR6 WGI Chapter 12). For the Mediterranean and southern Europe, warmer air masses can hold more moisture, leading to more intense downpours when favourable dynamical conditions are present. This can exacerbate pluvial and fluvial flooding, particularly in complex terrain such as the coastal and mountainous regions of Greece and Albania.

Our analysis approach rests on looking for weather situations similar to those of the event of interest having been observed in the past. For the Mediterranean Depression on 18-21/11, we have medium-high confidence in the robustness of our approach given the available climate data, as the event is similar to other past events in the data record.

ClimaMeter Analysis 

We analyze here (see Methodology for more details) how events similar to the meteorological conditions leading to the Mediterranean Depression on 18-21/11 have changed in the present (1987–2023) compared to what they would have looked like if they had occurred in the past (1950–1986) in the region [15°E 29°E 34°N 43°N]. The Surface Pressure Changes show that storms similar to this are up to 0.5 hPa deeper in the present climate, with an increase in the horizontal pressure gradient in the southeastern sector of the storms. Temperature Changes show that present-day events are up to +1 °C warmer in the depression’s warm sector compared to similar past storms. Precipitation Changes show wetter conditions, with up to +2 mm/day (or 5 to 15%) more rainfall. Windspeed Changes show significant increases of up to +4 km/h (+10 %) in coastal and offshore areas.

We also note a slight shift in storm seasonality: Seasonality diagnostics show that similar events occurred historically throughout October–December, but they now tend to occur relatively more often in late autumn and early winter, with an increased fraction of events in December. The long‑term frequency trend of analogues is slightly negative but not statistically significant within uncertainty, implying that the main detected changes concern intensity and persistence rather than overall frequency. Changes in urban areas reveal that Ioannina, Tirana and Durrës experience wetter conditions in the present than in the past.

Finally, we explore the role of large‑scale natural variability. The distributions of the El Niño–Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO) indices for past and present analogues do not show statistically significant differences. In contrast, the Pacific Decadal Oscillation (PDO) index displays a significant shift between the two periods, indicating that the background PDO state may modulate the occurrence of such events. Nevertheless, the detected thermodynamic changes in temperature and precipitation cannot be explained by PDO alone and are consistent with the influence of human‑driven climate change.

Conclusion

Based on the above, we conclude that depressions similar to this one are 0.5 hPa deeper, up to 2 mm/day wetter, and windier by up to 4 km/h (up to +10 %) in the present compared to the past. We interpret Greek-Albanian floods on 18-21/11 as an event of rare meteorological conditions for which human-driven climate change played a role.