LiPAD in use
Precision in permafrost: measurement technology for extreme conditions
At an altitude of almost 3,000 metres, the ground beneath the mountain station of Piz Nair, the famous local mountain of St. Moritz, is changing. Due to the melting of the permafrost as a result of global warming, the soil under the foundation is slowly losing its stability. What has for decades been considered permanently frozen in place is beginning to fall apart and shift as the temperatures rise. This creates a new engineering challenge for the existing infrastructure: how can stability be ensured in a subsurface which is constantly changing?
Dismantling the mountain station wasn’t an option. Instead, Engadin St. Moritz Mountains AG developed an innovative solution to preserve the existing structures and ensure their long-term sustainability. This has made Piz Nair the location of a unique project in Europe, showing how engineering, precision and modern measurement technology such as the LiPAD®-100 work together to keep buildings permanently stable, even under extreme conditions.
Stability under extreme conditions
Mountain stations such as the one on Piz Nair are among the most challenging structures in high mountain regions. They are required to withstand huge static and dynamic forces: cable and wind loads, large quantities of snow, stresses caused by low temperatures and frost, geotechnical stresses and seismic impacts. Stable foundations are the cornerstone for safe operations, and until recently, these were provided by the permafrost subsurface.
In the summer of 2025, an innovative approach to stabilising the subsurface was chosen to ensure the long-term future of the mountain station in the world’s oldest ski resort. For this purpose, 17 “thermosiphons” were used. These were drilled some 45 metres deep into the rock to specifically and permanently cool the soil for the future and ensure its load-bearing capacity. The passive systems are designed to dissipate heat from the ground and maintain the permafrost underneath the station over the long term.
The technology originated in the Alaskan oil industry where it is used to secure pipelines. A closed loop with CO₂ transports heat upwards from deeper layers of the soil, where it is released into the colder ambient air. The evaporation and subsequent condensation of the CO₂ in the interior of the thermosiphon results in a continuous heat dissipation which keeps the subsurface frozen. The thermosiphons don’t require an external energy supply, are completely self-sufficient and are considered to be a promising method for stabilising structures in other regions experiencing the thawing of permafrost.
Geometric precision as the basis
The realisation of the project required high-precision work in the rock. The holes for the thermosiphons had to be drilled underneath the existing mountain station at a challenging and flat angle along the planned axes. Even slight deviations would have affected the stability of the foundations as well as the existing facilities in the ground in an environment where readjustments are almost impossible and errors are unforgivable.
This is where traditional surveying methods reach their limits. Transporting equipment and survey teams to a height of 3,000 metres would have been complicated, weather-dependent and time-critical. The goal was therefore to find a precise, independent solution which could be directly integrated into the drilling process and enable an autonomous form of quality control.
This is where the LiPAD®-100 came into play. It is a compact, portable northfinder for high-precision alignment tasks, such as those involving drilling equipment. It was developed for harsh environments where conventional methods such as GPS or laser surveying reach their limits or are unreliable. The system is based on inertial measurement technology and combines fibre optic gyroscopes with a highly sensitive accelerometer triad. This allows the azimuth and the current tilt of the drill rig to be recorded in real time, without the need for GPS or external references. The measurement data is continuously available on the display, enabling corrections at any time during construction and also serving as a means of verifying the drilling results.
The LiPAD®-100 was integrated directly into the drilling process for the construction project in St. Moritz. It allowed the team to continuously monitor the orientation of the drilling equipment during the work. “We’re talking about high-precision drilling up to 45 metres in length, in challenging subsurface conditions, in a very confined space beneath existing infrastructure, and all while the lifts remained operational,” explains Thomas Brunner, Technical Director of the cable cars company. “An exact drilling path was crucial to ensure that each thermosiphon pipe was positioned exactly where it was needed for maximum cooling efficiency. The system enabled us to achieve a level of accuracy that would have been unattainable using conventional methods, guaranteeing successful completion within just two and a half months.”
The data was documented after each measurement, ensuring complete transparency and traceability of the entire drilling process. This allowed even the smallest deviations to be identified, assessed and corrected as required. “With the LiPAD®-100, we were able to independently monitor and document the drilling at all times,” says Thomas Brunner. “This saved time, reduced dependencies and increased safety because any deviation was immediately clear.”
“Especially in projects like this, where conventional measurement methods such as GPS are not an accurate option, the strength of a system that operates completely autonomously and simultaneously delivers the highest accuracy becomes clear,” adds Erik Bergmüller, Sales & Business Development Manager at LITEF. “This combination of durability and precision is crucial when it comes to construction projects under extreme conditions with particularly high safety requirements.”
Technology for the future
The design concept of the world-famous St. Moritz ski resort is unique in Europe and considered an innovative flagship project for new approaches to securing alpine infrastructure. The need for similar measures will continue to grow in the coming years. Numerous structures, such as mountain stations, restaurants, pylons, power lines, railway tracks and critical infrastructure in the Alps are built on permafrost, a subsurface which is irreversibly losing its stability due to rising temperatures. This increases the importance of innovative technical solutions which can respond to changing ground conditions and extend the lifespan of these structures by decades.
The installation of the thermosiphons on Piz Nair follows this very approach. The goal is to demonstrate the physical effects and long-term effectiveness of the method under real-world conditions in the alpine environment and to extend the safe operation of the mountain station by another 30 years. Crucial to this was the precision implementation within a very short timeframe.
The data collected will also be incorporated into the scientific and technical evaluation of the project. It will provide valuable insights into how changes in permafrost can be monitored, addressed and compensated for in future construction projects. In this way, the project not only contributes to the stabilisation of a single mountain station but also to the further development of geotechnical methods throughout the high-alpine region.
Precision measurement technology such as the LiPAD®-100 plays a key role in this area. It creates the conditions for reliably planning and implementing complex construction processes, also under extreme environmental conditions. And it demonstrates how innovation in engineering will be defined in the future: through the combination of experience, innovative technology and measurable precision.