Regional Mountain Conference

On Monday, 19th of May 2025, the village of Blatten in the Lötschental (VS, Switzerland) was completely evacuated because of alpine mass movements detected on the Kleines Nesthorn. On the same day, Geoprevent installed an interferometric radar that provided data on which the local authorities relied to manage the crisis. The radar recorded small movements of the mountain independent of rain, snow, fog or darkness and could therefore see movements that a human eye could not see.

Only one day before the Birch glacier collapse, Geoprevent installed a high-resolution camera on the Eastern moraine of the glacier to monitor the upper part of the glacier, that was masked by its front for the radar. These images revealed a dramatic picture during the last hours and showed a rapid movement of the glacier. With these images and the help of complex algorithms, Geoprevent could provide periodic analysis of the deformations of the Birch Glacier to support the local experts in their risk assessments.

During the crisis and afterwards, Geoprevent was mandated to install a comprehensive multi-component monitoring system of the Kleines Nesthorn, Birch and Nest glaciers. Altogether, an interferometric radar, two high-resolution camera systems, two pan-tilt-zoom camera and several GPS systems were installed. The data gathered provided key and unique insights into the processes happening before and after the collapse of the Birch glacier. The data is currently being post-processed and prepared to be made available for the scientific community. In this work we present an operation point of view.