Recent evolution of damage to infrastructure on permafrost in the French Alps

The past four decades have seen extensive development of the winter sport industry in the French Alps and several hundred ropeway transport systems have been installed in areas where mountain permafrost may be present. Due to current climatic change and the ensuing permafrost degradation, the vulnerability of these infrastructures to destabilization may increase. Therefore, there is a real potential for instabilities to develop on ropeway transport systems in the Alps, requiring a better understanding of these processes. This study investigates the relation between permafrost and infrastructure stability in the French Alps, seeking to understand the evolution of this phenomenon over the past decades. This was done by following a two-step analysis. At first, the infrastructure elements built on modeled permafrost-affected areas were inventoried at the scale of the French Alps in order to get an overview of the possible vulnerabilities. Then, our study presents a detailed historical inventory of damage to infrastructure over the past three decades in different geomorphologic contexts. Overall, in the French Alps, there are almost 1000 infrastructure elements located in permafrost areas among which 12 (i.e., 24 infrastructure elements) were identified to have been subject to repeated instances of disruption and deterioration and most of the damages recorded were in areas where permafrost degradation is fully expected (ice-rich terrain). Infrastructure recovery costs may be significantly high, making this issue a relevant consideration to be included in the design process.