Skip to main content

Roya Valley - Flood Disaster


After Storm Alex caused serious damage from floods and landslips in southeastern France, wireless tilt sensors were used to monitor the stability of a hospital during emergency repair works

Roya Valley_1
Roya Valley_2


In October 2020, storm Alex brought heavy rain and flooding to the Roya Valley - a mountainous region at the border between France and Italy. In France’s Alpes-Maritimes region, the floodwater destroyed buildings, bridges, and roads, isolating several villages.

The Saint-Lazare Hospital located by the Roya river, suffered extensive damage during the event.

In addition to the destruction of its gardens, the main building suffered a partial washout of its foundation piles. Two terraced balconies ended up suspended in the void and multiple cracks appeared on the walls.

65 residents were evacuated during the night of the disaster. The hospital site, closed to access, needed to be rebuilt. Ionyx Concept, a subsidiary of Ionyx Industrie Environnement, was selected by the main contractor to monitor the stability of the building during the emergency restoration works.


Senceive’s French distributor, Geomesure, was quickly on hand to offer their local expertise and assist in finding a monitoring solution for the building.

As the use of a traditional optical solution was technically impossible due to the inaccessibility and dangerous nature of the area, 16 Senceive wireless triaxial tilt sensors were selected to measure the movements of the unstable facade during repair works. Data was relayed from the sensors to cloud-based visualisation software WebMonitor™ via a mains free Gateway.

Data frequency was set to 15 minutes. The system provided an accuracy of around 0.09 mm and SMS and email alerts were set to provide near real-time alerts in the event of any movement exceeding predefined thresholds.

Senceive’s wireless FlatMesh™ platform allowed the project team to set all configuration parameters remotely. It provided a data stream continuously - 7 days a week, 24 hours a day, without the need to return to site.


This solution had the advantage of being fully autonomous in an area where there was no power due to the disaster. Both the sensors - with a 15 year battery life on standard reporting rate, and the solar powered gateway, were the ideal solution for this difficult-to-access environment.

The fast reporting capability of the FlatMesh™ platform gave stakeholders the confidence that any movements to the damaged building would be quickly detected.

The collaboration between a local surveyor, a regional distributor and Senceive ensured the highest level of support for this critical project.


Created on: Mon 12th Apr 2021