Detecting icing conditions such as those related to super cooled droplets and high density ice crystals is a very challenging task. Both these phenomena are very dangerous for Civil Aviation, therefore it is worth understand the ice formation and its physical evolution from nucleation to growth and secondary production. In this paper the main risks caused by ice to aircraft flight are described and the processes of ice cloudsformationandicinggrowtharediscussed.Atlast,themain polarimetric parameters useful for ice detection are examinated and some actions in the contest of European programs are described aimed to in-field experimental data collection.