Snowflakes or snow crystals form when ice crystals freeze around tiny particles of dust that are in the air and join together as they fall. Ice crystals that melt as they fall become rain. Ice crystals that form near the ground are called frost.
Snow blossoms on river rocks ~ Valley of Ice Flowers - Alessandro Zocchi "This is one of the coldest valleys in the Italian Dolomites. Sun never reaches the bottom in winter and nature can have its fun here creating spectacular ice formations.