CASE C09 · CH · 2024
Canton of Valais, Switzerland: drone survey of a road tunnel collapsed by landslides
In February 2024 landslides damaged a road tunnel in the Swiss canton of Valais. The next day the canton's own pilot flew a LiDAR drone inside and recorded the damage in 3D without sending people in. The tunnel reopened in June 2024, but time and cost savings were not quantified.
| Owner | Canton of Valais, Department of Mobility, Territory and Environment |
| Provider | — |
| Location | Riddes – La Tzoumaz, Valais, Switzerland |
| Aircraft | Flyability Elios 3 with Surveying Payload |
| Sensors | RGB photo/video, LiDAR |
Before
Investigators would first have had to secure the landslide area before collecting data; entering the damaged tunnel was not an option.
With drones
The day after the 3 February 2024 landslides, the canton's own pilot flew the drone into the tunnel and recorded the damage with images, video and LiDAR.
Outcomes
| Metric | Value | Basis |
|---|---|---|
| response time | pilot on site within 24 hours; tunnel interior surveyed the next day | Reported |
| reopening | tunnel reopened in June 2024 | Reported |
| time / team size | 'saved hours of work' with 'a much smaller team' (no figures) | Reported |
Caveats & limits
- Manufacturer case study; savings are not quantified.
- The drone gave remote data only; causal explanations (1960s window design, freeze–thaw, blasting) are investigators' inferences.
- No limitations of the drone are described.
Sources
- Investigating a collapsed tunnel after a landslide in the Swiss AlpsFlyability Full text read
Sources checked: 2026-10-22