Heavy rainfall across southeastern France on Wednesday triggered a dramatic flash flood in the Hérault department, causing the coastal river Lez to swell to 10 times its normal volume within hours, tf1info.fr reported. The sudden surge transformed a typically tranquil waterway into a raging torrent, prompting preventive evacuations in the commune of Lattes and leaving vehicles submerged in Castelnau-le-Lez as local authorities raced to manage the rising waters.
Flash Floods Transform the Lez Into a Raging Torrent
The severe weather system struck the region hard on Wednesday evening, pushing water levels in the Lez to critical thresholds. Residents living near the riverbank voiced astonishment at the rapid transformation of the landscape. "It’s the first time we’ve seen it this wide. It’s impressive," a local resident told tf1info.fr during on-the-ground coverage of the event.
In Castelnau-le-Lez, the overflowing river trapped several vehicles in rapidly deepening water. Homeowners scrambled to move their automobiles to higher ground before the interior cabins could be compromised. "There is water that got into the car behind. We’re going to move it to put it in safety, to prevent water from getting in again," one resident explained to reporters while navigating the rising floodwaters.
Disappearing Sluice Gates and Rising Stakes in Lattes
Further south along the river’s path, the Lez crosses multiple urban areas near Montpellier, where the water pressure continued to mount throughout the evening. In Lattes, residents noted that the infrastructure designed to control the flow had been entirely overwhelmed by the deluge. "It’s very impressive because at the base, there is a 5-meter drop. Boats are supposed to pass through the third lock of Lattes. And there, everything is at the same level," a local resident observed.
Living merely dozens of meters from the banks, residents faced an anxious night as the margin for safety vanished. "There is about 1.50 meters left before it reaches the banks. If it overflows the dike, that’s as many houses that can be flooded behind. There is no containment afterwards," another local pointed out, highlighting the lack of downstream barriers to absorb the overflow.
Emergency Response and Preventive Evacuations
Technical services units deployed along the Lez to clear out accumulated debris and obstacles, known as embâcles, to maintain optimal water drainage. Crews anticipated working through the night to monitor conditions. "We’re here until maybe 23h, midnight, 5 a.m. We are in the town hall crisis cell. People have been evacuated from different districts," said Jérémy Marin, an agent de maitrise.
As a strict safety measure, authorities carried out preventive evacuations late in the day, relocating residents from neighborhoods on the opposite bank to a designated municipal shelter. The emergency response remains active as the region continues to monitor the persistent weather threats associated with the active red alert for rain and flooding across the Gard and Hérault departments.
