It was discovered that the rissagas of Ciutadella came from Algeria.
In 1988 Diario Menorca reported that the Meteorological Centre in Palma had discovered that the rissagas or tidal waves affecting the port of Ciutadella originated in Algeria. Four years previously there had been a tide that could have sunk up to 70 boats and so an investigation was initiated.
The newspaper Diario Menorca reported that studies conducted on the cyclones of the Western Mediterranean showed that the tides that affect the port of Ciutadella have their epicenter on the Algerian coast. Deep depressions in the atmosphere of this North African country forced hot air over the Mare Nostrum which might otherwise have caused storms.
According to this hypothesis, the air from Algeria produced long waves that were amplified in many ports especially in the port of Ciutadella due to its structural configuration. A team from the Physics Department of the University of Balearic Islands concluded that the port of Ciutadella had a depth, length and width that caused the long waves going towards the port to extend up to two metres in height. The only solution to avoid these tidal waves was to structurally modify the port.
If the Algerian depressions became storms the consequences would be worse. Meteorologists attributed the Algerian depression that occurred in 1980 as the cause of the five metre waves that affected the port of Mahon, destroying 12 boats.