Final answer:
Snow forms when compacted and metamorphosed, turning into ice. This process is influenced by factors like temperature and air humidity.
Step-by-step explanation:
Snow forms as a result of snow that accumulates on land and then through compaction and snow metamorphism turns into ice. Snow is formed from ice crystals, which are the solid phase of water. The process of snow metamorphism occurs when the snow is subjected to pressure and changes in temperature, causing the ice crystals to rearrange and become denser. This process can take a certain amount of time, depending on factors such as temperature and air humidity.