The climate of freezing rain over the province of Québec in Canada: a preliminary analysis

After 20 yr of data gathering, the Hydro-Québec network of Passive Ice Meters (PIM) is producing interesting results, namely a map of the freezing rain season in the province of Québec. For other icing parameters, such as the icing frequency and the persistence of ice deposits on structures, differences were found very large and the preliminary analysis was limited to the St.-Lawrence valley. By pooling together maximum values of three stations, it was possible to produce coherent extreme values distributions. While many icing storms are unnoticed at meteorological stations, they seem to be well picked up by the fine grid network of PIM stations, with only 2 observations/day. It is thus possible to precisely map these values and produce better ice load zones for determining limit strengths of structures. The same data are also used to produce risk analyses of other problems related to structures such as flashovers of iced insulators or conductors galloping. Although all freezing rain storms are observed by the PIM network, there is a need for more detailed and more frequent observations during major storms. This will help the calibration of PIM measurements and improve our study of icing storms trajectories.