Regional landslide early warning systems in Italy

In Italy, landslides pose a recurrent hazard to human life and livelihood every year. For this reason, with the support of the Italian National Department for Civil Protection (DPC) we have developed a landslide early warning system named SANF (an Italian acronym for national early warning system for rainfall-induced landslides) to forecast the possible occurrence of rainfall-induced landslides in Italy (Rossi et al., 2012). The system uses (i) rainfall measurements from a network of about 3000 rain gauges, (ii) rainfall forecasts at different time intervals, (iii) probabilistic rainfall thresholds (Brunetti et al., 2010; Peruccacci et al., 2017), and (iv) a susceptibility map derived at national scale. Since 2008 the system has been running at national scale. Following the request of regional civil protection authorities of Liguria, Sardinia and Apulia, new SANF versions were developed at regional scale (SARF). While maintaining the structure of the system and the same approach in the calculation of the landslide occurrence probability, each SARF has been customized to cope with the specific user requirements. As an example, for the Liguria region SARF uses regional rainfall thresholds and an ensemble of forecasted rainfall models issued daily by the local environmental protection agency (ARPAL). Differently, the local agency of the Sardinia region (ARPAS) provides us the BOLAM rainfall forecast. After a proper running and validation period, SARF systems are expected to become a valid support for decision makers in forecasting rainfall-induced landslides at regional scale.