Drones revolutionize landslide safety
When a landslide occurs, it is critical to rapidly understand the situation without endangering lives. Drones have become an essential tool for NGI’s work with landslide mitigation and rock slope stabilization.
NGI’s drone pilots utilize drones to document landslide areas and assess terrain stability, thereby minimizing personnel exposure to unnecessary risk. ( Photo: Terje Pedersen / NTB)
Following landslides and rockfalls, the affected areas are often unstable. Cracks in the rock face can warn of new slides, and loose debris may still be in motion. For the geologists and engineers tasked with assessing the risk, drones have become a vital aid. When the soil and rock slide occurred at Carl Berner in Oslo in October 2025, drones played a decisive role in uncovering the danger of further slides.
"Drones allow us to collect information quickly and safely, even in locations where physical access is challenging," says Dyre Oliver Dammann, Head of Remote Sensing and Geophysics at NGI. "We obtain overview images, but we can also use drone data to generate detailed 3D models that make it easier to understand the terrain and fracture patterns in the rock."
Arnstein Aarset, Head of Engineering Geology and Rock Engineering at NGI, was on-site following the slide at Carl Berner. He believes drone data has become a natural component of interdisciplinary work regarding landslides and rock reinforcement.
"Drones provide an additional data foundation that complements field observations," Aarset notes. "They make it easier to plan measures, position bolts and anchors correctly, and discuss solutions within the team."
From Images to 3D Models
3D terrain models are developed using photogrammetry, where the drone captures numerous overlapping images from various angles. The software utilizes these images to calculate height and form, resulting in a realistic three-dimensional map of the area.
Where vegetation is dense or extra precision is required, laser scanning (LiDAR) is also employed. Laser beams have the advantage of penetrating tree canopies, allowing vegetation to be filtered out.
"Photogrammetry and LiDAR provide us with a highly detailed and reliable data foundation," Dammann explains. "We can observe changes in the terrain over time and detect minute movements that may indicate instability." "These are excellent planning tools for both securing against and preventing new slides."
He emphasizes that drones do not replace engineering geologists in the field but provide an extra layer of information and the opportunity to work more systematically.
"We receive a product and result that can be viewed, discussed, and compared with previous measurements," he elaborates. "This strengthens both the quality and efficiency of our work."
Dyre Oliver Dammann, Head of Remote Sensing and Geophysics at NGI, believes drone data is becoming a standard method in landslide mitigation and rock reinforcement. ( Photo: NGI)
Automated processes
NGI utilizes drones in both acute situations and long-term monitoring programs. One example is erosion measurement in quick clay zones, where municipalities are required to closely monitor developments.
"With a drone, we can document changes across large areas and calculate how many cubic meters have washed out since the last measurement," Dammann says. "This reveals a great deal about how rapidly erosion is developing, and consequently, the risk of slopes losing stability."
He notes that drone technology marks a distinct shift in how data collection is conducted.
"Manual measuring equipment can be extremely accurate, but we are now seeing field inspections and manual measurements increasingly being replaced by automated processes," he says. "Drone-based surveys are transitioning from being a specialized supplement to becoming a standard method for mapping and risk assessment."
The technology is also used in NGI’s own research projects, including the monitoring and modeling of various types of landslides.
Requires control and routines
Although drone technology offers significant opportunities, it also requires extensive permits and adherence to strict safety procedures. NGI collaborates closely with the operator company, Airwatch, to ensure that all flights are conducted safely and in compliance with regulations.
"This enables NGI to mobilize quickly and operate in areas with challenging terrain and complex conditions regarding natural hazards and strict regulations," says Dammann. "At the same time, we maintain high safety standards."
The technology enables NGI to work more safely, faster, and more systematically. It is a tool that provides new perspectives and facilitates easier cross-disciplinary collaboration.
"NGI strives to maintain skilled drone pilots at offices in Oslo, Trondheim, and Tromsø to be able to deploy on short notice when situations arise," Dammann states. "After several years of testing and field use, drone technology has become an integrated part of the work with landslide mitigation and rock reinforcement."
Dyre Oliver Dammann
Head of Section Remote Sensing and Geophysics dyre.dammann@ngi.no+47 930 10 310