Snow begins as ice crystals that form and grow in cold clouds. Their shapes depend on the conditions they encounter, including temperature and the availability of water vapour. Crystals can join together as they fall, producing flakes of different sizes. What reaches the ground may be light and powdery, dense and wet, or somewhere between these familiar descriptions.
The structure of a snowflake reflects the way water molecules arrange themselves in ice. The well-known six-sided pattern can develop many branches and variations as a crystal grows. Not every falling crystal has the elaborate shape shown in close-up photographs. Plates, columns, irregular fragments, and combinations of forms also occur. Changes within a cloud mean that neighbouring crystals may have followed different growth histories before reaching the same patch of ground.
Snow continues changing after it has fallen. The grains can settle, bond together, melt, or refreeze as conditions vary. A layer that was soft in the morning may develop a firmer surface later. Wind can move loose snow into drifts and leave other areas more exposed. These processes create a snow cover with different layers and textures, rather than one uniform blanket.
Snow cover influences the landscape beneath and around it. Its bright surface reflects much of the incoming sunlight, while air held between the grains can provide insulation. Water stored as snow can later enter the soil, streams, and rivers during melting. The timing of this release depends on weather, elevation, vegetation, and the depth of the accumulated snow. These connections make seasonal snow important far beyond the places where it first falls.
Simple observations reveal many of these changes. The outline of a drift, the texture of the surface, and the tracks left by animals show how snow interacts with wind and living activity. Comparing shaded and sunny ground can reveal different patterns of melting. Snow is not merely a temporary decoration on the landscape; it is a changing form of water with its own structure, movement, and role in seasonal cycles.