The Mediterranean Sea does not experience true hurricanes, but it is home to tropical-like cyclones known informally as “Medicanes,” a portmanteau of Mediterranean and hurricane. These weather systems exhibit characteristics similar to their tropical counterparts, including a central eye and spiraling cloud bands. While they are smaller and generally less intense than Atlantic hurricanes, Medicanes can still produce destructive winds and torrential rainfall. The phenomenon is a rare but recurring threat.
Why They Are Not True Hurricanes
The classification of a storm as a “hurricane” is based on meteorological criteria that Medicanes typically do not meet, particularly concerning sustained wind speed. A storm must achieve maximum sustained winds of 74 miles per hour (119 kilometers per hour) to be classified as a Category 1 hurricane on the Saffir-Simpson Scale. While some Medicanes have briefly achieved this threshold, they rarely maintain it for long, generally being comparable to a strong tropical storm.
A significant difference lies in the required sea surface temperature (SST) and the depth of the warm water beneath the surface. True tropical cyclones require SSTs of at least 80 degrees Fahrenheit (27 degrees Celsius) extending to a substantial depth for sustained intensification. The Mediterranean Sea, being a much smaller and shallower basin, generally lacks the deep reservoir of warm water found in the tropical Atlantic or Pacific Oceans. Therefore, the storms cannot fuel themselves long enough to reach the sustained intensity or size of a major hurricane. The term “hurricane” is also a purely geographical designation, reserved for storms in the North Atlantic and Northeast Pacific basins.
The Unique Formation of Medicanes
Medicane formation differs significantly from the genesis of typical tropical cyclones, which rely purely on warm water. Medicanes often begin as non-tropical, cold-core low-pressure systems, known as extratropical cyclones, similar to winter storms. They transition into a tropical-like system through a complex process involving the interaction of relatively warmer sea water and cold air high up in the atmosphere.
This interaction creates a steep temperature gradient, leading to high atmospheric instability. Deep convection, or strong upward movement of air, is triggered, which releases latent heat from condensing water vapor. This heat release warms the center of the storm, causing it to develop the warm-core structure characteristic of a tropical cyclone.
The Mediterranean Sea’s small size and proximity to land limit the duration and potential growth of these storms. Medicanes typically have a diameter of only 70 to 200 kilometers, substantially smaller than a major hurricane. Due to the limited distance over water, these systems have less time to intensify before encountering land or cooler water. This results in a much shorter lifespan, often lasting only a day or two in their most intense, tropical-like phase.
Frequency, Intensity, and Notable Events
Medicanes are rare, with the Mediterranean basin typically experiencing only one or two strong events annually. These storms most commonly form during the late summer and autumn months, from September to January. This timing occurs when the sea surface temperatures are at their warmest but cold air intrusions from the continent are also increasing. The most common areas for their formation are the Ionian Sea, the waters between Sicily and North Africa, and the western Mediterranean near the Balearic Islands.
While the winds from a Medicane can be damaging, the most hazardous aspect of these systems is the rainfall they produce, which frequently leads to flash flooding. On a few rare occasions, Medicanes have been observed to reach the intensity of a Category 1 hurricane. One notable event, Medicane Ianos in 2020, even reached the equivalent of a Category 2 intensity before making landfall in Greece.
Medicane Zorbas, which struck Greece in September 2018, caused significant flooding and wind damage. More recently, Storm Daniel in September 2023 became the deadliest Medicane on record, causing catastrophic flooding in Greece, Turkey, and Libya. These events highlight the serious threat Medicanes pose to the heavily populated coastal regions of Southern Europe and North Africa.