What is a medicane, the Mediterranean mini-hurricane that can reach Catalonia?

BarcelonaIn the Mediterranean, a type of atmospheric disturbance can occur that, due to its characteristics, can be associated with a tropical cyclone, although with less intensity and smaller dimensions: the medicanes. The term medicane comes from the fusion of Mediterranean and hurricane. This phenomenon is nothing more than a quasi-tropical depression formed by its own warm core, induced by a large concentration of latent heat resulting from condensation. The energy released by this large storm translates into the formation of large stormy nuclei, with torrential rains, very strong surface winds, and violent phenomena, such as intense electrical activity, waterspouts, tornadoes, and maritime storms. If we observe it through satellite images, it is often accompanied by a kind of eye that resembles, in a certain way, the structure of a hurricane.

This violent weather lasts a few hours, but its consequences can be disastrous, as, for example, in the case of the medicane Daniel, which was one of the most catastrophic in the Mediterranean, with exceptional rainfall records and a death toll that exceeded 5,200 people in Libya in 2023.

One of the most important factors for the formation of a medicane is that the sea temperature is high, and for this reason, it is common for them to appear in late summer and autumn. This summer, for example, records of the average surface temperature of the Mediterranean were registered, reaching 28.6 °C on August 14, 2026, according to data from the Copernicus Marine Service.

Warming of the Mediterranean

In Catalonia, the sea has reached its highest average temperature on record this summer: 21.1 °C. It is more than evident that, in the Mediterranean, the warming of the waters is 20% faster than in the rest of the seas or oceans, with anomalies relative to the average that, in some places, already exceed 4 °C. All of this is the perfect breeding ground for the formation of extreme and violent phenomena, such as mini-hurricanes, which feed on the huge amount of water vapor emitted by the warm sea.

In 2007, one formed between the coasts of Alicante, Murcia, and the Balearic Islands, which caused strong winds and downpours in these areas. And in 1986 –when the term medicane did not yet exist– a small Mediterranean cyclone also affected the island of Mallorca. It is, therefore, a phenomenon that will become increasingly likely in the coming years. It must be taken into account that medicanes are storms of much smaller sizes than hurricanes and usually do not exceed category one on a scale of five. They are less than 200 kilometers in diameter, while hurricanes can be 400 to 800. Their strong winds can reach 150 km/h compared to the 300 km/h that hurricanes can reach.

In our case, during the early hours of Sunday, there is a low probability that this medicane will form. Various meteorological models, such as AROME, indicate the formation of a convective vortex that would approach the central Catalan coast, with strong gusts of wind and intense precipitation, and with accumulations exceeding 200 mm. This convective phenomenon generates great uncertainty. We repeat that it is an unlikely scenario, but, in the event that it does occur, it is quite dangerous. However, whether the medicane forms or not, the downpours and torrential rains will discharge with force due to the formation of large storm systems, just as the models currently indicate.