Development and Implementation of the Risk Concept for Natural Hazards

In the Alpine biosphere, natural hazards cannot be prevented entirely. Despite the substantial sums that have been invested in avalanche barriers and check dams, such hazards repeatedly endanger people and destroy buildings and transportation routes. Against this background, safety experts have begun to adopt a new approach. In the past they sought to prevent natural hazards with every available means, but their focus is now turning to reducing the risks associated with such hazards. In a technical context, risk is defined as the probability of damage expressed in monetary units or fatalities occurring within a defined period (e.g. one year). The strategy adopted by the National Platform for Natural Hazards (PLANAT) in 2004 made this notion of minimising risk (risk concept) the focal point of its approach to natural hazards. A similar concept for managing risk has long since been put into practice in other fields, including in the civil use of nuclear energy.

PLANAT Action Plans

Within the framework of its action plans for 2005 - 2008 and 2009 – 2011, PLANAT closed various gaps in order to fully implement the risk concept. As a key foundation for the concept, it commissioned the SLF to oversee production of a code of practice for managing risk (project A1.1 Risk Concept). The code of practice describes the theoretical basis of the concept and illustrates practical ways of reducing the risk of natural hazards from an economic, ecological and social perspective (sustainability principles).

During the project “Effect of Mitigation Measures” (project A3 – PROTECT) generally applicable foundations as well as measure- and process-specific tools for the consideration of mitigation measures during hazard assessment were developed in collaboration with external partners.

During the project “Vulnerability due to Natural Hazards” (project A5 – Vulnerability) foundations were developed to assess the existing vulnerability functions for buildings with respect to avalanches, debris flows, flooding and rock fall.

All reports on the PLANAT action plans can be downloaded from www.planat.ch.

New calculation tools

The risk management code of practice makes it clear that action has to be taken during a natural hazard event (intervention), as well as after (recovery or reconstruction) and before (prevention) such an event. The goal is to find a combination of planning, technical, biological and organisational measures that is capable of minimising the risk (accomplishing the desired benefit) while incurring as little cost as possible. In order to calculate the cost-benefit ratio, the SLF has joined forces in recent years with other institutions to develop a variety of instruments (EconoMe-Tools). They are being used by expert agencies and public authorities as an aid to prioritizing protective measures. The tools also raise the users' awareness of the risk-based approach and enable them to explain more clearly to those concerned the reasoning behind decisions in favor of certain measures. Sharing information about risks is a key element of risk management. Managing risk successfully depends on the public at large accepting the authorities' decisions and contributing themselves to reducing the risks that accompany natural hazards. Although natural hazards continue to represent a major challenge, especially against the backdrop of climate change, safety experts can now use the risk concept to engage in a more effective evaluation and discussion of various scenarios and courses of action.

EU-Project IRASMOS

During the project IRASMOS scientists from Switzerland, Austria, Italy, France and Norway pooled the existing expert knowledge on natural hazards management from their respective countries and analysed it under the aspect of “best practice”. In the context of IRASMOS Christoph Rheinberger’s dissertation, titled “Economic Evaluation of Mitigation Measures against Natural Hazards”, investigated the individual willingness to pay for the protection against natural hazards of different groups of people. (Rheinberger, Ch. 2009: Preferences for Mitigating Natural Hazards on Alpine Roads: A Discrete Choice Approach, Diss ETH No. 18476).

The project IRASMOS was concluded in 2008. Information and results can be accessed on irasmos.slf.ch.