Portuguese researchers studied an “exceptional sequence” of seven atmospheric rivers in less than a month.
A series of seven atmospheric rivers swept across the Iberian Peninsula between January and February. The phenomenon was studied by researchers at the University of Évora.
The Iberian Peninsula was hit by an “exceptional sequence” of seven atmospheric rivers in less than a month, between January and February of this year, a phenomenon observed and studied by the University of Évora, it was announced this Sunday (11).
“We had an exceptional sequence of atmospheric rivers during that period, with very significant consequences for the territory,” said Miguel Potes, director of the Research Center in Science and Technology for the Earth and Energy System (CREATE) at the University of Évora (UÉvora).
According to the researcher, this sequence of events constituted, at the same time, “a unique opportunity to observe the atmospheric processes associated with moisture transport.”
To study what was happening above the surface, the university participated in an international campaign to “study physical and dynamic processes” that “trigger strong winds and precipitation and intrusions of dry air in the North Atlantic and the Euro-Mediterranean region,” also analyzing “what is represented in weather forecasting models,” explained the University of Évora.
This campaign, he emphasized, “had the fortunate coincidence of occurring during a winter with several exceptional episodes of wind and precipitation in Europe, and especially in the Iberian Peninsula,” which was hit by “seven atmospheric rivers” during that period.
The events in January and February left soils saturated and reservoirs full, causing flooding, the University of Évora noted.
At the same time, he stressed, they offered “a rare opportunity to observe, at altitude, the atmosphere that carried large amounts of moisture from the Atlantic.”
In the Alentejo region, “the rain left a particularly noticeable mark.”
In February, CREATE stations recorded 252.8 millimeters of precipitation in Portel, 243.8 in Évora, and 252.1 at the Polo da Mitra station, 12 kilometers from this city.
“These figures are part of an exceptionally intense rainfall episode in mainland Portugal which, according to the Portuguese Institute of the Sea and the Atmosphere (IPMA), made February 2026 the rainiest February in the last 47 years and the fifth rainiest since 1931,” the statement reads.
As part of the EUROP project – European University RadioSonde Partnership, 14 radiosondes were launched from the Atmospheric Sciences Observatory of CREATE in Évora.
“Radiosondes are small instruments carried by a helium-filled balloon that rise through the atmosphere and measure, among other variables, temperature, humidity, pressure, and wind,” the researcher explained.
The goal is to “understand what is happening in the atmosphere at altitude, monitoring the structure and transport of moisture during the passage of these systems.”
The data collected “have a second life beyond the research” because they are used for numerical weather forecasting models , which means the research can have consequences for the future.
“The question is not only whether an atmospheric river will reach the Iberian Peninsula. It is necessary to predict its trajectory, the amount of moisture it carries, and how that moisture will interact with other air masses to produce precipitation,” emphasized Miguel Potes.
The CREATE team at the University of Évora, composed of researchers and doctoral students, is preparing for a new campaign in the upcoming winter, intending to carry out new radiosonde surveys “during the passage of meteorological systems of interest” for the research.