They occur mainly in mountainous areas but can also develop in any areas with reasonably steep slopes. During the summer of 2023, the large rainstorm “Hans” triggered debris flows in Åre municipality with costly and extensive damage to both infrastructure and buildings.
Debris flows are not a new phenomenon in Sweden. Many traces of past events have been documented using remote sensing. However, there are also many events that has not been documented or reported as they occurred without affecting either infrastructure or people.
Climate change is expected to lead to an increase in frequency and intensity of extreme precipitation, which in turn can lead to an increased frequency of debris flows. Such effects are expected to be greater in the mountains with long steep slopes, particularly where infrastructure development is taking place in sloping terrain. The project intends to develop tools to reduce society's vulnerability through analysis of the distribution of historical debris flows, both in time and space, and to develop understanding of the debris flow process through field studies in selected areas.
The work includes:
- Collection of data for events from various sources.
- Analysis of weather data associated with these events to identify precipitation thresholds.
- Instrumentation in pilot areas to better understand conditions for debris flows.
The project is being carried out in close contact with authorities and municipalities.
