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Damage caused by floods, debris flows, landslides and fall processes

Floods, debris flows, landslides and fall processes can cause significant damage. The extent of the damage is influenced by the use of built-up area and the intensity and spatial extent of the natural hazard events. Hence it also depends on the measures taken to protect human life, the environment and material assets. The amount of losses associated with such events is an indicator of, first, the success of the preventive measures implemented to protect against natural hazards and, second, the vulnerability of buildings and infrastructure.

Assessment of the state
poor poor
Assessment of the trend
impossible to evaluate impossible to evaluate
Damage caused by floods, debris flows, landslides and fall processes 2024: 905.06 Damage caused by floods, debris flows, landslides and fall processes 2023: 73.3927460992908 Damage caused by floods, debris flows, landslides and fall processes 2022: 46.0268154158215 Damage caused by floods, debris flows, landslides and fall processes 2021: 475.770914779484 Damage caused by floods, debris flows, landslides and fall processes 2020: 42.6663110578365 Damage caused by floods, debris flows, landslides and fall processes 2019: 87.6385629277001 Damage caused by floods, debris flows, landslides and fall processes 2018: 217.854735742013 Damage caused by floods, debris flows, landslides and fall processes 2017: 186.440042194093 Damage caused by floods, debris flows, landslides and fall processes 2016: 104.363509090909 Damage caused by floods, debris flows, landslides and fall processes 2015: 157.438383107089 Damage caused by floods, debris flows, landslides and fall processes 2014: 107.102526096033 Damage caused by floods, debris flows, landslides and fall processes 2013: 132.991046511628 Damage caused by floods, debris flows, landslides and fall processes 2012: 41.3757482891997 Damage caused by floods, debris flows, landslides and fall processes 2011: 125.60522606383 Damage caused by floods, debris flows, landslides and fall processes 2010: 65.9935989336492 Damage caused by floods, debris flows, landslides and fall processes 2009: 27.7134029227557 Damage caused by floods, debris flows, landslides and fall processes 2008: 24.4335103857567 Damage caused by floods, debris flows, landslides and fall processes 2007: 767.404138297869 Damage caused by floods, debris flows, landslides and fall processes 2006: 80.8711543172078 Damage caused by floods, debris flows, landslides and fall processes 2005: 3304.07947988863 Damage caused by floods, debris flows, landslides and fall processes 2004: 54.3597338760175 Damage caused by floods, debris flows, landslides and fall processes 2003: 82.0760492268854 Damage caused by floods, debris flows, landslides and fall processes 2002: 395.652537313433 Damage caused by floods, debris flows, landslides and fall processes 2001: 91.8762080536914 Damage caused by floods, debris flows, landslides and fall processes 2000: 827.179547449967 Damage caused by floods, debris flows, landslides and fall processes 1999: 799.104967213111 Damage caused by floods, debris flows, landslides and fall processes 1998: 50.4601338400529 Damage caused by floods, debris flows, landslides and fall processes 1997: 231.683338842975 Damage caused by floods, debris flows, landslides and fall processes 1996: 40.9093953488372 Damage caused by floods, debris flows, landslides and fall processes 1995: 100.482327528466 Damage caused by floods, debris flows, landslides and fall processes 1994: 256.382935560861 Damage caused by floods, debris flows, landslides and fall processes 1993: 1117.65232806052 Damage caused by floods, debris flows, landslides and fall processes 1992: 78.107541740675 Damage caused by floods, debris flows, landslides and fall processes 1991: 158.939294161124 Damage caused by floods, debris flows, landslides and fall processes 1990: 398.802296557121 Damage caused by floods, debris flows, landslides and fall processes 1989: 21.0253731958763 Damage caused by floods, debris flows, landslides and fall processes 1988: 188.788987664824 Damage caused by floods, debris flows, landslides and fall processes 1987: 1883.92853119583 Damage caused by floods, debris flows, landslides and fall processes 1986: 191.869507692308 Damage caused by floods, debris flows, landslides and fall processes 1985: 82.9052347209921 Damage caused by floods, debris flows, landslides and fall processes 1984: 171.980444342648 Damage caused by floods, debris flows, landslides and fall processes 1983: 92.2751485148516 Damage caused by floods, debris flows, landslides and fall processes 1982: 73.0760922330098 Damage caused by floods, debris flows, landslides and fall processes 1981: 97.0780461538462 Damage caused by floods, debris flows, landslides and fall processes 1980: 49.3293555434191 Damage caused by floods, debris flows, landslides and fall processes 1979: 95.1482954545454 Damage caused by floods, debris flows, landslides and fall processes 1978: 1114.42838728664 Damage caused by floods, debris flows, landslides and fall processes 1977: 544.517965496729 Damage caused by floods, debris flows, landslides and fall processes 1976: 40.2876566265061 Damage caused by floods, debris flows, landslides and fall processes 1975: 344.052187500001 Damage caused by floods, debris flows, landslides and fall processes 1974: 68.9297187704381 Damage caused by floods, debris flows, landslides and fall processes 1973: 243.3991959799 Damage caused by floods, debris flows, landslides and fall processes 1972: 47.0894535519125
*adjusted for inflation, based on 2024 prices
Data for the graph: Excel | Source: WSL

Comment

Between 1972 and 2024, floods and debris flows caused damage to the tune of around CHF 15.7 billion. The damage caused by landslides and fall processes totalled at 1.3 billion. Hence, the total cost of damage arising from these natural events was CHF 17 billion; this corresponds to an average annual cost of CHF 320.9 million (all values are adjusted for inflation, based on 2024 prices).

The damage in 2024 is approximately 12 times greater than that in 2023. The state is therefore considered poor. The trend is not evaluated because the strong annual fluctuations and the relatively short observation period do not allow for a clear statement.

The total amount of damage is mainly influenced by a few major events: the floods of August 2005 caused around CHF 3.3 billion in damage (adjusted for inflation), and half of all damage can be attributed to the five largest events – most recently exacerbated by the floods and landslides in 2024.

According to nationally available data, approximately 1.8 million people, that is around 20 percent of the Swiss population, live in areas at risk from flooding. Approximately 1.7 million or 30 percent of the country’s jobs are also located in such areas and around 25 percent of material assets (total approximately CHF 840 billion[1]) can be found in potential flood areas. A large proportion of economic value creation also takes place there. The existing protective infrastructure protects these areas against frequent flood events. Without this protective infrastructure, losses would be significantly higher.

Absolute safety in dealing with natural hazards is impossible to achieve. The analysis of major flood events, in particular the OWARNA project, have shown that consistent implementation of modern flood protection strategies and improved alerting and alarm systems would enable the avoidance of up to 20% of the damage. For this reason the indicator state is evaluated as medium. The development is not evaluated as the strong annual fluctuations and relatively short monitoring period do not allow clear conclusions to be drawn.

Method

As mandated by the Federal Office for the Environment, the Swiss Federal Institute of Forest, Snow and Landscape Research WSL has been collecting data systematically on storm damage in Switzerland since 1972. The hazard processes floods, debris flows, landslides and rockfall are surveyed. The surveys are mainly based on reports from approximately 3,000 Swiss newspapers and magazines and – in the case of extensive hazard events – the information provided by the cantons and insurance companies. Fact sheets on the five hazard processes mentioned above can be downloaded from the Gefahrenprozesse (not available in english).

[1] According to the study “Die volkswirtschaftliche Bedeutung der Immobilienwirtschaft der Schweiz “ (“The economic significance of the property market in Switzerland”) (Staub P., Rütter H., 2014), the construction value of Switzerland’s buildings is CHF 3,355 billion.

 
Last updated on: 25.11.2025