Rogithon I – A week of rock glacier mapping across Switzerland
From February 5th to 9th 2024, eight members of the RoDynAlpS project met in Ovronnaz (VS) for a dedicated working week on Work Package 1. This package focuses on assessing and quantifying the current state of rock glaciers in Switzerland. The objective was to identify and locate as many rock glaciers in Switzerland as possible.
Methodology
The team applied the first step of the International Permafrost Association’s (IPA) Rock Glacier Inventory and Kinematics (RGIK) guidelines, which involved placing a point (a “Primary Marker”) within a GIS project on each detected rock glacier unit.
The investigations primarily relied on a dataset provided by Swisstopo, which included current and historical aerial orthoimages, topographic maps, as well as the latest digital elevation model, known as the Swiss Surface 3D Raster and derived from airborne LiDAR data (spatial resolution of 0.5 m). Additionally, the operators used SAR interferograms produced by Gamma Remote Sensing from Sentinel 1 images acquired between 2020 and 2022. The investigations mainly focused on areas above 1000 m a.s.l., excluding the Berne canton due to unavailability of the Swiss Surface 3D Raster DEM at that time. The study area was divided into 500 sub-areas, each assigned to a team operator.
Results
At the end of the Rogithon week, around 9000 rock glacier units had been provisionally identified, including around 2000 uncertain rock glacier units that require further investigation (e.g. field visits) to either confirm or dismiss as many as possible. Plus, in order to minimize subjectivity as much as possible, a double-check will be carried out by a restricted number of operators.
