Snow is nothing but frozen water, and ice has no colour. Yet snow looks white in colour.
This is because each snowflake is mode up of a number of ice-crystals having many surfaces. When light reflects from all these surfaces, it makes the snow look white.
Snow is formed when water vapour present in the atmosphere freezes. This results in the formation of clear, transparent crystals and the currents of air make these crystals go up and down in the atmosphere.
Below Snow info from Wikipedia (Read More):-
Snow is a type of precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by external pressure. Snowflakes come in a variety of sizes and shapes. Types which fall in the form of a ball due to melting and refreezing, rather than a flake, are known as graupel, with ice pellets and snow grains as examples of graupel. Snowfall amount, and its related liquid equivalent precipitation amount, are determined using a variety of different rain gauges.
The process of precipitating snow is called snowfall. Snowfall tends to form within regions of upward motion of air around a type of low-pressure system known as an extratropical cyclone. Snow can fall poleward of their associated warm fronts and within their comma head precipitation patterns, which is called such due to its comma-like shape of the cloud and precipitation pattern around the poleward and west sides of extratropical cyclones. Where relatively warm water bodies are present, for example due to water evaporation from lakes, lake-effect snowfall becomes a concern downwind of the warm lakes within the cold cyclonic flow around the backside of extratropical cyclones. Lake-effect snowfall can be locally heavy. Thundersnow is possible within a cyclone's comma head and within lake effect precipitation bands. In mountainous areas, heavy snow is possible where upslope flow is maximized within windward sides of the terrain at elevation, if the atmosphere is cold enough.
http://en.wikipedia.org/wiki/Snow
