![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/Idrometri-Toscana-1024x455.avif\" "\\"\\"")
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The situation worsened as the hours passed due to the continuous moisture inflow sustained by strong southwesterly winds, which intensified the event. <\/p>\n\n
To understand the causes of this extreme weather phenomenon and assess its impact, CIMA Research Foundation conducted a detailed analysis, integrating advanced meteorological data and satellite imagery to reconstruct the event’s dynamics and support emergency management activities. <\/p>\n\n
How much rain fell? Observed data <\/h2>\n\n
On March 14, 2025, Tuscany recorded exceptional rainfall accumulations in several locations. According to data provided by the LaMMA Consortium, the cumulative precipitation reached significant values: <\/p>\n\n
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- Province of Florence: up to 150 mm in 24 hours, with peaks of 180 mm in some stations.<\/li>\n<\/ul>\n\n
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- Province of Pisa: between 120 and 140 mm in 24 hours.<\/li>\n<\/ul>\n\n
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- Province of Livorno: average values of 130 mm in 24 hours, with local peaks up to 160 mm.<\/li>\n<\/ul>\n\n
These figures represent extraordinarily high rainfall amounts, which contributed to the rapid rise of river levels and subsequent flooding. The spatial distribution of precipitation showed greater intensity in the inland areas of the region, particularly in the provinces of Florence and Pisa. <\/p>\n\n
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![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/myDewetra-PluvioRadar-1024x537.avif\" "\\"\\"")
Fig. 2. Cumulative precipitation map for March 14, 2025, obtained by integrating radar and rain gauge data. The image highlights the areas with the highest precipitation levels, particularly in central Tuscany, where peaks exceeding 150 mm in 24 hours were recorded. <\/figcaption><\/figure>\n\n <\/p>\n\n
Why did it happen? A meteorological analysis <\/h2>\n\n
The flood event was driven by a low-pressure system over southern France, which channeled highly humid air masses toward Tuscany. \u201cImagine a large spiral of unstable air constantly drawing moisture from the ocean and the Mediterranean,\u201d explains Elena Oberto, researcher in the Meteorology and Climate department of CIMA Research Foundation. \u201cThis type of configuration can generate intense rainfall that persists over the same areas for several hours.\u201d <\/p>\n\n
ECMWF analyses show that as early as the early hours of March 14, an intense precipitation zone formed along a southwest-northeast axis, particularly affecting the provinces of Livorno, Pisa, and Florence, with continued activity over the following 24 hours. <\/p>\n\n
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\n\n![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/ECMWF-1-1024x734.avif\" "\\"\\"")
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<\/figure>\n<\/div>\n<\/div>\n\nFig. 3,4,5. ECMWF maps for March 14, 2025, at 00UTC, 12UTC, and March 15 at 00UTC, provided by the Functional Center of the Aosta Valley: these maps illustrate geopotential height and temperature at 500 hPa, highlighting the atmospheric configuration that drove the intense precipitation in Tuscany. <\/p>\n\n
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Soil moisture conditions before the event also played a crucial role. Analyses show that soil moisture levels were already elevated on March 12, 2025, reducing the ground\u2019s capacity to absorb further rainfall.<\/p>\n\n
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![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/Soil-moisture-12-marzo-1024x478.avif\" "\\"\\"")
Fig.6. Soil moisture map for the Italian territory on March 12, 2025. <\/figcaption><\/figure>\n\n <\/p>\n\n
This situation was exacerbated by wind convergence in the lower atmospheric layers and strong sirocco winds in southern Tuscany, which further fueled precipitation. \u201cAnother key factor,\u201d Oberto adds, \u201cwas the strong southwesterly wind at about 1,500 meters altitude. This created the perfect conditions for persistent rainfall, resulting in very high accumulations over a short period.\u201d <\/p>\n\n
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![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/ECMWF-vento-1024x733.avif\" "\\"\\"")
Fig. 7. ECMWF map for March 14, 2025, at 00UTC, provided by the Functional Center of the Aosta Valley: it shows wind patterns at 850 hPa (approximately 1,500 m altitude), highlighting strong southwesterly winds over the regions most affected by the extreme weather event, particularly Tuscany and Emilia-Romagna. <\/figcaption><\/figure>\n\n <\/p>\n\n
The heavy precipitation also had effects beyond Tuscany, impacting the central-eastern part of Emilia-Romagna, where river levels rose significantly, and landslides were reported.<\/p>\n\n
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\n\n![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/Livello-idrometrico-ER-ARPAE-1024x572.avif\" "\\"\\"")
Fig. 8. Map of hydrometric levels observed at 00:00 UTC on March 15, 2025, acquired via telemetry from the regional hydrometeorological network of Emilia-Romagna, provided by ARPA Emilia-Romagna. <\/figcaption><\/figure>\n<\/div>\n\n\n\n \n![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/Precipitazione-cumulata-ER-ARPAE-1024x572.avif\" "\\"\\"")
Fig. 9. Map of daily cumulative precipitation (in mm) for March 14, 2025, provided by ARPA Emilia-Romagna. <\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n <\/p>\n\n
Where did it impact? Satellite monitoring <\/h2>\n\n
On the afternoon of March 14, the Italian Civil Protection Department activated Fondazione CIMA in collaboration with the Italian Space Agency (ASI) to monitor the flooded areas using satellite imagery. \u201cSatellites are fundamental tools for understanding what happened and how the situation evolved in the following hours,\u201d explains Giuseppe Squicciarino, researcher in Earth Observation at CIMA Research Foundation. \u201cThanks to Sentinel-1 and the Cosmo Second Generation (CSG) constellation, we obtained detailed images of the affected areas.\u201d <\/p>\n\n
\n\n![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/CSG-13.03.2025_1-1024x603.avif\" "\\"\\"")
Fig. 10. CSG image from March 15, 2025, acquired in the late afternoon on a descending orbit. The scene covers Florence and the surrounding municipalities, including Sesto Fiorentino, Campi Bisenzio, Calenzano, and Poggio a Caiano. <\/figcaption><\/figure>\n<\/div>\n\n\n\n \n![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/Sentinel1-17.03.2025_1-1024x603.avif\" "\\"\\"")
Fig. 11. Sentinel-1 image from March 17, 2025, acquired in the early morning. Due to its extensive coverage, this image captures the entire course of the Arno River, from Florence to its mouth. <\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n <\/p>\n\n
On March 15, a CSG observation provided by ASI enabled the acquisition of high-resolution images (3 meters), covering Florence and nearby municipalities such as Sesto Fiorentino, Campi Bisenzio, Calenzano, Poggio a Caiano, and parts of the province. On March 17, Sentinel-1 acquired a new image with a wider coverage (250 km swath), allowing for an analysis of the entire Arno River course from Florence to its mouth. <\/p>\n\n
![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/CSG-15.03.2025_a-1024x419.avif\" "\\"\\"")
Fig. 12. CSG image from March 15, 2025, at 17:56 UTC. The scene shows the flooded areas. <\/figcaption><\/figure>\n\n ![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/CSG-15.03.2025_b-1024x420.avif\" "\\"\\"")
Fig. 13. <\/em>CSG image from March 15, 2025, at 17:56 UTC. The scene shows the flooded areas. <\/figcaption><\/figure>\n\n ![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/Sentinel-17.03.2025_c-1024x420.avif\" "\\"\\"")
Fig. 14.<\/em> Sentinel-1 image from March 17, 2025, at 05:27 UTC. The scene captures the entire course of the Arno River, from Florence to its mouth, highlighting the flood-affected areas due to the sensor\u2019s wide coverage. <\/figcaption><\/figure>\n\n <\/p>\n\n
\u201cThese images provided us with a comprehensive representation of the event. We were able to compare the situation before and after the flood, identify flooded areas, and assess the evolution of the flooding phenomenon in the following days. Such data are crucial for supporting authorities in emergency management and planning intervention strategies,\u201d concludes the researcher.<\/p>\n\n
<\/p>\n\n
A rare or recurrent event in the climate context?<\/h2>\n\n
The March 14, 2025, event stands out due to the extraordinary amount of rainfall recorded within 24 hours. According to Antonio Parodi, Program Director at Fondazione CIMA, \u201cIf we compare the observed rainfall with the March climatology, based on 40 years of ERA5 data at 3 km resolution, we see that in some areas of Tuscany, the 24-hour rainfall amounted to 300% of the monthly average. This highlights the significance of the phenomenon, but not necessarily its rarity when compared to past extreme events like the 2017 Livorno flood.\u201d <\/p>\n\n
- Province of Livorno: average values of 130 mm in 24 hours, with local peaks up to 160 mm.<\/li>\n<\/ul>\n\n
- Province of Pisa: between 120 and 140 mm in 24 hours.<\/li>\n<\/ul>\n\n
![\"\"](\"https:\/\/www.cimafoundation.org\/wp-content\/uploads\/2025\/03\/anomaly_MCM_14032025_ch-1024x662.avif\" "\\"\\"")
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