Courchevel reservoir under surveillance
- The retenue d'eau de la Loze reservoir at 2,270 metres in Courchevel is under surveillance after authorities found a structural defect linked to fragile permafrost terrain. - Geomorphologist Ludovic Ravenel highlighted that warming permafrost is weakening frozen cementation and changing ground behaviour at the site. - The case shows monitoring and re-evaluating ground models where thermal change can alter foundation and slope performance. (radiofrance.fr)
1/ Courchevel’s La Loze reservoir is a useful case study in how climate change can become an engineering problem through the ground itself, not only through heat, drought or extreme rain. The structure sits at 2,270 meters, where part of the foundation terrain includes permafrost that is no longer behaving as a fixed base. (podcastaddict.com) 2/ The immediate issue is not a theoretical risk. France Inter reported a structural defect at the reservoir, and other French media said the site had experienced subsidence and a leak, prompting partial emptying and closer surveillance. (podcastaddict.com) 3/ The reservoir was created in 2020 to support artificial snowmaking for Courchevel’s Eclipse slope, according to Le Dauphiné. The same report said it can store 170,000 cubic meters of water and was built ahead of the 2023 Alpine Ski World Championships. (ledauphine.com) 4/ The key technical point is what Ludovic Ravenel, a geomorphologist cited by France Inter, described: warming affects terrain made of permafrost because frozen ground loses part of the “cementation” that had been holding it together. When that frozen bond weakens, deformation patterns can change. (podcastaddict.com) 5/ Permafrost is not just “cold soil.” In engineering terms, it can act like a material whose strength and stiffness partly depend on ice remaining in place. Once temperatures rise, the same slope or foundation can respond differently even if the visible structure above it has not changed. This is an inference drawn from Ravenel’s explanation of warming permafrost and the reported defect at La Loze. (podcastaddict.com) 6/ That is why this story matters beyond ski infrastructure. A design can be compliant when built and still become less reliable later if the ground model assumed a thermal regime that no longer holds. In Courchevel, the concern is not only the reservoir liner or embankment in isolation, but the support conditions under and around the structure. This is an inference supported by the reported subsidence, leak and expert findings. (france3-regions.franceinfo.fr) 7/ The timeline also matters. Le Dauphiné reported that an expert report delivered in December 2025 identified the problem, and that securing works were to be carried out. That places the current surveillance in a post-construction monitoring phase, not at the original design stage. (ledauphine.com) 8/ Another useful detail is that Courchevel operator S3V has publicly said it launched a study to better understand permafrost distribution in the Courchevel and Méribel-Mottaret ski areas. That suggests the issue is being treated as a broader natural-risk question for mountain infrastructure, not as a one-off defect at a single basin. (s3v.com) 9/ For engineers, the lesson is straightforward: where thermal conditions are changing, surveillance is part of the structure. Instrumentation, repeat inspections, movement tracking and periodic re-checks of the geotechnical model become as important as the original calculations. The La Loze case is a reminder that “ground conditions” are not always static over an asset’s life. (podcastaddict.com) 10/ For everyone else, the Courchevel story is a concrete example of climate risk showing up in infrastructure through slow physical change. The next step to watch is the securing work and any updated findings from local authorities, S3V or experts following the December 2025 report and the surveillance now underway. (ledauphine.com)
