A system capable of detecting the hazardous accumulation of ice on the surfaces, engines, instruments and air intakes of aircrafts or other objects of interest. The system consists of an electromagnetic microwave resonator capable of detecting the formation of ice directly where it could cause problems. The sensor could be mounted around the air intake of pitot tubes, static ports, engines intake, engines core, and can be embedded in the aircraft skin. The system uses algorithms based on the variations of the complex dielectric permittivity of water substance with frequency to distinguish the various types of ice from each other and from water.