Chemists at the University of Utah discovered that ice forms at temperatures as low as minus 55 degrees Fahrenheit, according to a Science Daily article. Prior to this discovery, scientists believed ice formed exclusively at 32 degrees Fahrenheit.
Solid ice crystals mix with what University of Utah chemists refer to as "intermediate ice" formed from super-cooled water just prior to uniform freezing, according to the Science Daily article. Intermediate ice maintains some of the structure of liquid. The molecular structure of water changes prior to freezing, forming tetrahedron shapes. In transitioning from intermediate ice to solid ice, these molecules then interlock with four other tetrahedron-shaped molecules.