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In Switzerland, natural hazards such as avalanches, landslides, rockfall, debris flows, flooding and forest fires can cause considerable damage. Through our research and services, we help to protect people from natural events.


In Switzerland, 23 people are killed on average each year by avalanches alone; flooding and mass movements cause damage amounting to an average of CHF 300 million per year. As the population continues to grow, more and more buildings are located in at-risk areas.

As such, we look into how different natural hazards arise, how far, how quickly and how vigorously they develop, and how people can protect themselves accordingly. This may be through effective spatial planning, reliable forecasting or technical protective measures. We lay the scientific foundations for risk analysis and for evaluating whether protective measures and warning systems are effective and economical.

As well as scientific and engineering research, this requires economic and social analysis given that major events present politics, government and society with the challenge of finding widely accepted and economically viable risk reduction strategies.

Observation and simulation

In order to understand the processes of natural hazards in detail, we run experimental setups which are unique worldwide. As part of field experiments, we observe the dynamics of avalanches, debris flows, rockfall and landslides under realistic conditions. In some cases, we also initiate them for experimental purposes (avalanche test site).

Thanks to this measurement data, we now understand better than ever how these natural hazards arise, and are able to simulate the processes within them in increasingly precise computational models. This is useful for developing protective measures and hazard maps.

Contending with climate change

When glaciers melt and permafrost thaws as a result of climate change, this threatens to set in motion enormous quantities of soil, rock and scree – a significant danger to lower lying settlements and transportation infrastructure. This is why we are focusing on mass movements in alpine regions that are triggered by climate change as part of the strategic research initiative "Climate Change Impacts on Alpine Mass Movements", which is set to run from 2017 to 2020.

Forewarned and informed                                                                               

When it comes to warning and prevention systems, we play an important role nationally and occupy a leading position internationally: in winter, the avalanche warning service at the WSL Institute for Snow and Avalanche Research SLF publishes the well-known avalanche bulletin twice a day, while our hydrologists are involved in warning the public about instances of flooding and severe drought.

Forest fires present a real threat in the already dry southern alpine valleys. We record and analyse forest fire events, develop methods and concepts to evaluate the risk of forest fire, and determine the consequences for ecosystems such as protection forests.

We make our data and findings available to the public on internet platforms so that crisis managers can access the information quickly in an emergency.



Ein Bord mit einigen kleinen Bäumen steht in Flammen. Die im Vordergrund sichtbaren grossen Bäume sind noch unversehrt.

Forest fires

We examine factors that increase the risk of forest fires and develop tools for predicting them.

Umgestürzte Bäume liegen in einer Lichtung.

Weather and Climate Extremes and Drought

We study weather and climate extremes in Switzerland, for example droughts. This is how we create the basis for dealing with them.

Ein Murgan stürzt sich in einem Bachbett hinunter.

Debris flows and bedload

Mountain torrents on steep terrain can sweep away destructive loads of rock. We investigate these processes to improve protection measures.

Zwei mit mehreren Personen besetzte Schlauchboote fahren durch die von Hochwasser überfluteten Gassen in einer Stadt.

High water levels and flooding

Flooding causes a huge amount of damage in Switzerland. We have been laying the foundations for flood forecasting and warnings for over 100 years.

Ein Stein prallt in einer Staubwolke in ein Steinschlagnetz.

Rockfalls and landslides

We research rockfalls, rock slope failures, hillslope debris flows and landslides to give people and infrastructure in valleys better protection.

Vor der Gemeindeverwaltung in Brienz, einem grossen Holzhaus, türmen sich Schlamm- und Geröllmassen von einem Murgang. Verschiedene Autos liegen kreuz und quer davor.

Dealing with natural hazards

Responding to and managing natural hazards has a long tradition in Switzerland. Through research and services, we help to reduce the risks.



The shape of rocks is a key factor in assessing rockfall hazard. This is the conclusion of a new SLF study.

The Intergovernmental Panel on Climate Change publishes its 6th scientific analysis of the global climate. A WSL researcher is co-author.

We are investigating the impact of forest structures on the groundwater balance and their ability to protect against landslides.

A huge mass of ice is threatening to fall from a glacier at the Italian side of Mont Blanc. Computer simulations help to determine safety measures.




Schall, P.; Heinrichs, S.; Ammer, C.; Ayasse, M.; Boch, S.; Buscot, F.; Fischer, M.; Goldmann, K.; Overmann, J.; Schulze, E.; Sikorski, J.; Weisser, W.W.; Wubet, T.; Gossner, M.M., 2021: Among stand heterogeneity is key for biodiversity in managed beech forests but does not question the value of unmanaged forests: response to Bruun and Heilmann‐Clausen (2021). Journal of Applied Ecology, 58, 9: 1817-1826. doi: 10.1111/1365-2664.13959

Wermelinger, B.; Rigling, A.; Schneider Mathis, D.; Kenis, M.; Gossner, M.M., 2021: Climate change effects on trophic interactions of bark beetles in inner alpine scots pine forests. Forests, 12, 2: 1-16. doi: 10.3390/f12020136

Warum können Steine schwimmen, sind die Tage des Aletschgletschers gezählt, wieso archivieren Bäume das Klima? Acht Wanderungen durch das Mittel- und Oberwallis führen an Orte, die Antworten auf solche Fragen liefern – dorthin, wo geforscht wird. Die Eidg. Forschungsanstalt für Wald, Schnee und Landschaft WSL befasst sich in dieser Region seit dreissig Jahren mit Lebensräumen und Naturgefahren und gibt nun entlang von Wanderwegen faszinierende Einblicke in ihre Arbeit. Hintergrundinformationen zu einzelnen Tier- und Pflanzenarten und eine App für unterwegs ergänzen den reich bebilderten Wissenschafts- und Wanderführer.