Indicator natural hazards

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
medium medium
Assessment of the trend
impossible to evaluate impossible to evaluate
Damage caused by floods, debris flows, landslides and fall processes 2022: 44.58 Damage caused by floods, debris flows, landslides and fall processes 2021: 460.815443980915 Damage caused by floods, debris flows, landslides and fall processes 2020: 41.3251303566078 Damage caused by floods, debris flows, landslides and fall processes 2019: 84.883716155906 Damage caused by floods, debris flows, landslides and fall processes 2018: 211.006649746193 Damage caused by floods, debris flows, landslides and fall processes 2017: 180.579451476793 Damage caused by floods, debris flows, landslides and fall processes 2016: 101.082927272727 Damage caused by floods, debris flows, landslides and fall processes 2015: 152.489435897436 Damage caused by floods, debris flows, landslides and fall processes 2014: 103.735845511482 Damage caused by floods, debris flows, landslides and fall processes 2013: 128.810581395349 Damage caused by floods, debris flows, landslides and fall processes 2012: 40.0751353763761 Damage caused by floods, debris flows, landslides and fall processes 2011: 121.656928191489 Damage caused by floods, debris flows, landslides and fall processes 2010: 63.9191439573459 Damage caused by floods, debris flows, landslides and fall processes 2009: 26.842254697286 Damage caused by floods, debris flows, landslides and fall processes 2008: 23.6654629080119 Damage caused by floods, debris flows, landslides and fall processes 2007: 743.281414893614 Damage caused by floods, debris flows, landslides and fall processes 2006: 78.3290355174527 Damage caused by floods, debris flows, landslides and fall processes 2005: 3200.21843533418 Damage caused by floods, debris flows, landslides and fall processes 2004: 52.6509799624296 Damage caused by floods, debris flows, landslides and fall processes 2003: 79.4960555380246 Damage caused by floods, debris flows, landslides and fall processes 2002: 383.21552238806 Damage caused by floods, debris flows, landslides and fall processes 2001: 88.9881543624162 Damage caused by floods, debris flows, landslides and fall processes 2000: 801.177832795351 Damage caused by floods, debris flows, landslides and fall processes 1999: 773.985754098357 Damage caused by floods, debris flows, landslides and fall processes 1998: 48.8739606741573 Damage caused by floods, debris flows, landslides and fall processes 1997: 224.400561983471 Damage caused by floods, debris flows, landslides and fall processes 1996: 39.6234418604651 Damage caused by floods, debris flows, landslides and fall processes 1995: 97.3237474882787 Damage caused by floods, debris flows, landslides and fall processes 1994: 248.323747016708 Damage caused by floods, debris flows, landslides and fall processes 1993: 1082.51983837689 Damage caused by floods, debris flows, landslides and fall processes 1992: 75.6522948490231 Damage caused by floods, debris flows, landslides and fall processes 1991: 153.943167036216 Damage caused by floods, debris flows, landslides and fall processes 1990: 386.266271517998 Damage caused by floods, debris flows, landslides and fall processes 1989: 20.3644577319587 Damage caused by floods, debris flows, landslides and fall processes 1988: 182.854559761804 Damage caused by floods, debris flows, landslides and fall processes 1987: 1824.70877383015 Damage caused by floods, debris flows, landslides and fall processes 1986: 185.838246153846 Damage caused by floods, debris flows, landslides and fall processes 1985: 80.299176262179 Damage caused by floods, debris flows, landslides and fall processes 1984: 166.574379294549 Damage caused by floods, debris flows, landslides and fall processes 1983: 89.3745544554456 Damage caused by floods, debris flows, landslides and fall processes 1982: 70.779004854369 Damage caused by floods, debris flows, landslides and fall processes 1981: 94.026476923077 Damage caused by floods, debris flows, landslides and fall processes 1980: 47.7787274713273 Damage caused by floods, debris flows, landslides and fall processes 1979: 92.1573863636364 Damage caused by floods, debris flows, landslides and fall processes 1978: 1079.39723955268 Damage caused by floods, debris flows, landslides and fall processes 1977: 527.401487209995 Damage caused by floods, debris flows, landslides and fall processes 1976: 39.0212469879518 Damage caused by floods, debris flows, landslides and fall processes 1975: 333.237187500001 Damage caused by floods, debris flows, landslides and fall processes 1974: 66.7629692609548 Damage caused by floods, debris flows, landslides and fall processes 1973: 235.748140703518 Damage caused by floods, debris flows, landslides and fall processes 1972: 45.6092349726775
*adjusted for inflation, based on 2022 prices

Data for the graph: Excel
Source: WSL on behalf of FOEN
Comment

Between 1972 and 2022, floods and debris flows caused damage to the tune of around CHF 14.3 billion. The damage caused by landslides and fall processes totalled at 1.2 billion. Hence, the total cost of damage arising from these natural events was CHF 15.5; this corresponds to an average annual cost of CHF 304 million.

The amount of losses is primarily dictated by individual hazard events. For example, the floods of August 2005 alone generated damage totalling around CHF 3.2 billion (adjusted for inflation). Half of the damage is accounted for by the five biggest individual hazard events.

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.

Damage can be prevented or limited if the the hazards are known. Therefore the compilation of hazard maps, their continuous updating and their consistent implementation are matters of extreme urgency. Hazard potential can be limited through hazard-appropriate land-use. Buildings and infrastructure must be designed in a way that avoids major damage. Preventive measures (e.g. hazard prevention structures) must be designed in a robust way which ensures that they withstand excess loads and are able to be adapted to new conditions (climate change). The residual risks must be limited through comprehensive emergency planning and optimised warning and alerting systems.

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 (since 2002) 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.

[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: 06.11.2023

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