PERILS

PERILS is developing operational tools to quantify the impact of global warming on natural hazards in mountainous areas (landslides, rockfalls), by combining satellite imagery and in-situ data. It aims to create a gravitational activity indicator and a cartographic demonstrator for Alpine territory managers, which can be adapted to other mountain ranges.

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Mountainous area in Savoie affected by numerous landslides linked to global warming. © A. Mathy (SAGE Ingénierie, August 2025)

Operational tools for quantifying the impact of climate change on natural hazards in mountain areas

Overview

Context

Global warming is amplifying natural hazards in mountainous areas (landslides, rockfalls, mudslides), particularly at high altitudes (>2000 m), where the thawing of permafrost and changes in precipitation are destabilising slopes. This shift in the activity of gravitational processes is endangering infrastructure and residents in the valleys.

Against this backdrop, the PERILS (outils oPErationnels pour quantifier l’impact du changement climatique sur les RIsques natureLS en montagne) project aims to develop operational tools, based on satellite imagery and in-situ data, to quantify and monitor the evolution of these risks, drawing on previously validated methodologies (OTELO project, Space Tour 2021).

Methodology

The use of time series of satellite imagery enables the dynamics of ground movements to be documented and monitored. The PERILS project draws on the expertise of the Alpine Geotechnical Company - Société Alpine de Géotechnique (SAGE) - and EOST (University of Strasbourg) to adapt and deploy already validated satellite image processing pipelines (OTELO remote sensing tools).

Objective

PERILS aims to provide managers of mountainous areas (local authorities, ski resorts, national parks) with a reliable and updatable indicator of gravitational activity within a given area. An online mapping demonstrator will enable the vizualisation of risk trends and raise awareness among local stakeholders.

Application site(s)

France :

Savoie / Les Arcs resort
Alpes de Haute Provence Department: middle and upper Ubaye valley

Data

Satellite

Sentinel-1 and COSMO-SkyMed (CSK) synthetic aperture radar images
Multispectral images Sentinel-2, Spot6/7, Planet CubeSAT/DOVE

Other

In-situ sensor measurements (GNSS, extensometers, network of tacheometric prisms)
Airborne LiDAR data

Results – Final product(s)

Aimed at managers and stakeholders in mountainous areas, PERILS will provide the following:

Maps and time series of ground movements detected at pilot sites through satellite image analysis
Inventory of new unstable areas to complement existing inventories.
Advanced inventories with information on object kinematics.
An online web service enabling the vizualisation of inventoried gravitational instabilities at pilot sites, with a slider to model the impact of climate change.
Awareness-raising workshops organized within the regions.