Characterization of rainfall events corresponding to forecasted conditions of potential hydrogeological risk

The Italian territory has a high exposure to natural risks including floods and landslides. An early warning system run by the Department for Civil Protection, both at national and regional level, operates to forecasted conditions of potential hydrogeological risk on the basis of forecasted meteorological conditions. The aim of the present paper is to study the relationship between the level of alert issued by the Civil Protection and the characteristics of the associated rainfall events. The case study is a particular area of the Campania region, highly prone to hydrogeological risk. A database of 138 warnings issued during the period 2018-2019 has been analyzed. The warnings were classified using analytical and graphical methods with various criteria. The duration, total rainfall, peak intensity, return period, nindex, BSC-index were used. The results show that there is a clear correlation between the severity of the warnings and the cumulative, peak intensity and the structure of precipitation. No relationship has instead been found between the severity of the warnings and the severity of the rainfall event which, besides the limitation of the case study with a small sample of analyzed events, can be an indication of changing climate conditions