Menorca is facing a significant meteorological warning from Aemet, including the possibility of rissagas. This phenomenon, also known as a meteotsunami, is primarily caused by variations in atmospheric pressure, unrelated to seismic activity or astronomical tides.
A rissaga manifests as a sudden surge of waves causing a notable alteration in sea level, particularly during high tide. This rapid rise and subsequent fall, which can occur within minutes or even seconds, can inflict considerable damage on moored vessels and port infrastructure.
The specific configuration of harbors is crucial for this phenomenon to occur. The port of Ciutadella, in Menorca, with its southwest-facing entrance and elongated, narrow shape, is particularly susceptible to rissagas.
“"There is up to a 70% probability of a sea level oscillation of up to 0.7 meters occurring throughout this Wednesday along the entire coast of Menorca."
The last major rissaga recorded in Ciutadella, the most significant in two decades, occurred on June 15, 2006. On that occasion, oscillations reached up to four meters, causing substantial damage to numerous boats.
The moments preceding a rissaga are characterized by a remarkable withdrawal of water from the port, causing vessels to touch the bottom. Immediately afterward, the water returns violently, overflowing the docks and lifting sailboats and yachts.
Meteorologists such as Agustí Jansà and Climent Ramis described in 1983 the favorable meteorological conditions in the Balearic Islands for these events. These include strong southwesterly winds at high altitudes, warm African air with a thermal inversion layer, instability in mid-levels, and, at the surface, east-southeasterly winds with cloudy skies and frequent mud rains.
