Navigation mit Access Keys

SLF HomeNatural hazards

Natural hazards

Main menu


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 hazards.


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.

We research 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 spatial planning, reliable forecasting, technical protective measures or protection forests. We lay the scientific foundations for risk analysis and evaluating whether protective measures and warning systems are effective and economical.

This requires not just scientific and engineering research, but economic and social research, as well as close cooperation between different stakeholders. The question of how to deal with natural hazards presents 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.


Thanks to these field experiments, we now understand better than ever how these natural hazards arise and develop, and are able to simulate the processes with increasingly precise computational models. This is useful for optimising 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, thereby endangering 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 information 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 avalanche bulletin. for Switzerland 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, findings and products available to the public and safety authorities on internet platforms, as apps or in leaflets.



This boulder had a diameter of 3.5 m. Image: Werner Gerber


We research rockfalls so that risks can be assessed and damage prevented, and develop instruments for research and practical use.

Image: Lambert Zufferey

Debris flow

Our software RAMMS::DEBRISFLOW makes it possible to calculate these debris flow processes and evaluate the effect of protective measures.


Image: Marcia Phillips/SLF


Flooding is caused by prolonged rainfall or heavy snowmelt, or a combination of these two events. Floods pose a threat to people, animals and...

Vallée de la Sionne avalanche test site. Image: SLF Archive


One of our core responsibilities entails investigating how avalanches arise, the forces they unleash, and how to defend against their effects.

Blick von oben auf den Auffangdamm für Lawinen und Murgänge und die darunterliegenden Häuser in Pontresina. Bild: Martin Heggli, SLF

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 posed by...



The year was marked by the arrival of the new director and the launch of strategic programmes and a research centre in Davos.

An international team of researchers has now been able to measure and simulate the resonant swaying of the Matterhorn.

The new grant, in memory of the former director of WSL, should strengthen cooperative research on natural hazards between Switzerland and Greenland.

Peter Bebi is the head of the CERC, the new SLF research centre combining expertise on climate change, extreme events and natural hazards.