overhead power lines in Italy Paolo Bonelli*, Lacavalla Matteo** 13th International Workshop on Atmospheric Icing of Structures. IWAIS 2009 Andermatt, (CH), 8-11 Settembre 2009 * ERSE SpA **COLLABORATORE A PROGETTO The wet-snow events are one of the most critical meteorological conditions that cause electric failures during winter season in Italy. The damages of the electric power lines can be direct or indirect: in the first case the ice load on conductors breaks the support of the wires; in the second case others elements close to the line, for example plants, fall into the tower lattice due to the ice load and wind force together. ERSE has started a specific research program in order to investigate this phenomenon, through an experimental activity designed to assess the accretion of ice on conductors during these events. This paper consists of three parts. The first one describes the collection of the field data and the criticality of some measurements. The second one is devoted to verify the wet-snow weather forecasting developed by ERSE. The final part concerns the study of sensibility of ice accretion models proposed by CIGRE and their applications to the field data.