Beyond the Expected—Residual Risk and Cases of Overload in the Context of Managing Alpine Natural Hazards

Structural protection measures are designed to protect the population and infrastructure against natural hazards up to a specific predefined protection goal. Extreme events with intensities that exceed the capacity of these protection structures are called ‘‘cases of overload’’ and are associated with ‘‘residual risks’’ that remain after the implementation of protection measures. In order to address residual risks and to reduce the damages from overload events, a combination of structural protection measures with additional, nonstructural measures is required. Based on data collected through a literature review, a questionnaire survey, expert interviews, and an expert workshop we highlight the status quo as well as key challenges of dealing with residual risks and cases of overload in Alpine countries in the context of geohydrological hazards and gravitational mass movements. We present a holistic conceptual framework that describes the relationships of residual risks, cases of overload, and protection goals in the context of both risk governance and integrated risk management. This framework is valuable for decision makers aiming at an improved management of natural hazards that takes adequate account of residual risk and cases of overload in Alpine countries and mountain areas worldwide.