Sea recedes suddenly in Nice in 1979

On 16 October 1979, around 2 p.m., the sea suddenly receded in front of Nice before returning to the coast of the Alpes-Maritimes. This unusual event was followed by a massive wave that affected nearby areas, including Antibes.

Water rises and causes damage in Antibes

In La Salis and La Garoupe, in Antibes, the water rose up to 3.5 meters and penetrated up to 150 meters inland. The wave caused significant damage, with boats ending up on roads, cars floating, and some vehicles perched in trees or on traffic lights.

Cause of the wave identified

Researchers Sahal and Lemahieu, in a study published in 2011 in the journal Natural Hazards, established that the event was caused by the collapse of a 300-meter seawall on a port construction site. Seismographs recorded this collapse, not an earthquake.

Construction site and its impact

The construction site, located at the mouth of the Var, south of the Nice airport platform, was launched in 1975 and was one of the largest public works projects in Europe at the time. It aimed to expand the airport and build a new commercial port, despite torrential rains in the autumn of 1979.

Details of the collapse

A section of the seawall collapsed at approximately 1:57 p.m., taking a dozen workers, 4 trucks, and 2 cranes with it. The disappearance of the seawall lasted approximately 4 to 5 minutes, according to an article by P. Habib in the Revue française de géotechnique.

Volume of the collapse debated

The volume of the collapsed material remains debated. The Conseil d'État estimated it at around 8.7 million cubic meters, while a 2000 study by Assier-Rzadkiewicz and colleagues estimated about 10 million cubic meters. Even at 9 million, this is equivalent to nearly 3,600 Olympic-sized pools.

Impact of the wave

The sea dropped more than 2 meters in the port of Nice, and two waves hit the coast from the Italian border to Antibes. The effects were felt from Hyères to Menton, with the water agitation in Antibes lasting approximately half an hour.

Human toll and aftermath

At least 8 people were killed in the incident, with some sources suggesting up to 11 fatalities. Construction workers accounted for the majority of the victims, with 9 dead or missing. A merchant and an 83-year-old woman also died in La Salis.

Submarine damage and long-term effects

The sediment flow traveled 150 kilometers in the Var canyon, reaching depths of up to 2,600 meters and severing two submarine cables located 80 and 110 kilometers from the coast. This event highlighted the potential dangers of such construction projects.

Preceding signs of instability

The accident did not arise out of nowhere. Researchers had recorded 110 subsidence episodes before the rupture, with settlements reported on 27 July and 26 September 1979. Torrential rains and a decadal flood peak in the Var added to the risks.

Scientific explanations and lack of consensus

A team of researchers proposed a creep model to explain the rupture, suggesting that sensitive clay under the weight of fill slowly gave way. However, no single cause has been universally accepted, with groundwater pressure and the Var flood also considered.

Legal ruling and consequences

In 1991, the Conseil d'État ruled the incident a force majeure, despite years of expert evaluations. The commercial port was never built, but the airport kept the land gained from the sea, with its runways partly resting on the construction site.

Commemoration and memory

A plaque at Terminal 2 of the Nice Côte d'Azur airport recalls the disaster, and a commemoration is held every 16 October. While travelers may not stop to reflect, the memory remains among residents of Antibes and Nice who lived through the day.

Preparedness and recognition

In June 2026, the Nice Côte d'Azur metropolitan area received the UNESCO Tsunami Ready label, following Cannes, which was labeled in January 2024. This program evaluates territories on 12 indicators, including evacuation maps and public information.

Tsunami risk and response time

Researchers estimate that a locally generated tsunami could reach certain areas of the Côte d'Azur in less than 10 minutes, highlighting the importance of preparedness. This is faster than the 10 to 15 minutes that passed between the sea receding and the wave returning in 1979.