One diver killed, second missing after Biarritz cliff collapse traps underwater explorers

A 34-year-old female diver was killed and a second diver remains missing after thousands of cubic metres of cliff collapsed into the Bay of Biscay at Biarritz on Thursday morning, French authorities confirmed. Rescue operations were suspended late on Thursday as investigators warned of further instability along the 25-metre-high limestone escarpment.

The disaster occurred shortly after 09:30 local time when a section of the Stele de la Vierge cliff face, measuring approximately 30 metres by 15 metres, detached without warning. Divers who had been exploring the underwater caves at the base of the cliff were struck by the falling rock. One woman, identified by local prosecutors as Claire Moreau, 34, from Bayonne, was pronounced dead at the scene. Her companion, 38-year-old Thomas Leroy of Anglet, has not been located despite a 12-hour search involving 23 coastguard vessels, two helicopters and 47 rescue divers.

Prefect of the Pyrénées-Atlantiques department, Jean-François Colombet, told reporters that Leroy’s disappearance was now considered a recovery operation rather than a rescue. “The volume of rock is such that we cannot rule out that he is trapped beneath the debris,” Colombet said. He added that the cliff face remained under continuous surveillance and that access to the area had been closed to the public indefinitely.

Geologists from the University of Bordeaux, who arrived on site within two hours of the collapse, attributed the incident to a combination of heavy winter rainfall and the natural erosion of the Urgonian limestone that characterises the Basque coast. “The cliff was already monitored for instability,” said Professor Élise Durand. “But the sheer scale of this failure suggests a sudden structural failure rather than a gradual slip.”

The tragedy has prompted calls for a national review of coastal safety protocols. Biarritz mayor Maider Arosteguy announced an immediate moratorium on all diving activities within 500 metres of the Stele de la Vierge and pledged to install additional warning sirens along the promenade. “We cannot bring Claire back, but we can prevent another family from suffering the same loss,” Arosteguy said.

Divers’ associations across the Atlantic Pyrenees region have suspended all cliff-base dives pending the outcome of the inquiry. The French maritime authority has dispatched a team of engineers to assess the structural integrity of the remaining cliff face, with results expected by Friday evening.