Drilling of new permafrost boreholes at Adlersruhe (3.454 m) in September 2025

GEORESEARCH and Land Salzburg are establishing Austria’s third site for direct permafrost monitoring - two new 20-meter boreholes on the Großglockner will help track permafrost changes

As part of the FROST.INI project (Interreg VI-A Italia-Austria 2021-27), two new permafrost boreholes were drilled from 4 to 6 September at 3,450 m above sea level, immediately north and south of the Erzherzog-Johann Hut (“Adlersruhe”). Beside Hoher Sonnblick (measurements since 2010) and Kitzsteinhorn (measurements since 2015), Adlersruhe now represents the third site in Austria where direct permafrost temperature measurements are being conducted.

Permafrost conditions have a significant impact on rock and slope stability. In order to accurately assess climate change-driven permafrost degradation, direct monitoring of thermal subsurface conditions via deep boreholes is essential. Understanding permafrost conditions and their temporal changes is a central foundation for evaluating rockfall risks, ground settlement, and structural stability. Additionally, the measured borehole temperatures serve to calibrate and validate permafrost distribution models. The two 20-meter deep boreholes at Adlersruhe are currently the highest‐elevation boreholes in the Eastern Alps (and the third highest borehole site in the entire Alpine region) and will provide valuable insights into changes in the subsurface thermal regime and the dynamics of climate-driven permafrost decline.

The two boreholes at Adlersruhe were drilled by Felbermayr using compressed-air hammer drilling with a diameter of 95 mm. After completion of the drilling, the boreholes were visually checked using an inspection camera. Along the full depth profile, the boreholes remained dry; no inflow of fracture or meltwater was observed. The upper decimetres in both boreholes consisted of a thin layer of unconsolidated debris, which, with increasing depth, transitioned into a fractured bedrock zone. From approximately 3 meters depth (southern borehole) and 5 meters depth (northern borehole), compact, unfractured bedrock (prasinite) was encountered.

Following camera inspection, the boreholes were fitted with a PVC pressure pipe sealed at the bottom, which serves as casing for the planned temperature sensors (instrumentation with temperature measurement chains is scheduled for October). Finally, the annular space — the volume between the PVC pipe and the surrounding bedrock — was filled with a fast-setting cement grout.