Ice fog and frost occurs very often in the northern latitudes and Arctic regions during winter, and ice fog at temperatures (T)<-20°C can occur about 20% of time. Ice fog is strongly related to frost formation that is a major reason for deicing the aircraft, in fact, it may be considered more dangerous than snow because it can stick on the aircraft surface more than snow particles. The goals of this work are to better understand 1) physical processes for ice fog formation, 2) its relation to frost occurrence, 3) its importance for aviation, and 4) develop skills for its nowcasting using remote sensing and surface observations, and forecasting models. At the low temperatures, snow/ice crystal water equivalent (SWE) can be very low e.g. 2-3%, and it can be swept by very low wind speed e.g. 1 m/s. Therefore, major reasoning for use of deicing chemicals in the north is likely related to the frost and ice fog conditions. During Fog Remote Sensing and Modeling (FRAM)-ICE project, approximately 40 different sensors used for collection of observations that include various visibility, precipitation, and ice particle spectra, and also a Profiling Micro Wave Radiometer (PMWR) based vapor mixing ratio, T, and liquid water content, and satellite based fog coverage. During the project, snow precipitation almost never exceeded more than 6 cm per day and entire 2 months time period, total snow amount was about 20 cm with SWE about 3-5% usually. Clear skies were dominant approximately 60% of time and an inversion layer existed almost everyday between surface and 1 km height. The ice fog during project was not predicted by the any forecast. The results of the project and related challenges in the northern latitudes will be presented.