The observations at the city and the suburbs of Asahikawa disclosed the areal distributions of supercooled dense fog and ice fog. At the central part of the city a supercooled dense fog seemed to be converted to an ice fog by artificial ice nuclei even at -14--17°C, when in the suburbs sometimes stable supercooled fog was observed at -26°C. It was also confirmed that ice crystals near the vapor sources grew sometimes so large that they might be called snow crystals.