Seven Years of Landslide Forecasting in Norway—Strengths and Limitations

The experiences acquired by the Norwegian Landslide Forecasting and Warning Service during the first 7 years of operation are herein presented. We summarize the warnings sent in the period 2013–2019 and we present the evaluation of the warning performance and discuss some of the main strengths and limitations of the service. In our opinion, of imperative importance to the success is: A national political will, the assignation of the landslide service to an existing well consolidated flood warning service and a strong collaboration across public agencies and a multidisciplinary approach. The existence of a national landslide database and of an operational distributed hydrological model, was essential for the rapid establishment of relationships between landslides events and hydro-meteorological conditions. A strong development of IT-tools and expansion of the meteorological and hydrological network was also crucial. Yet there are still several challenges and limitations, such as an insufficient process-understanding of rainfall- and snowmelt-induced landslides. The verification of landslide occurrence is also a difficult and tedious task. Finally, another challenging task is the prediction of landslides triggered by local intense rainshowers during summer, and rapid snowmelt events during winter, due to the limitations that exist in the models and thresholds currently in use.