Where does snow come from?
We notice activity in the air only when there is a result we can see, It i.e. wind, rain, frost and so on. But before we see these results there are a lot of happenings.
A snowflake begins as a single drop of water, suspended in the air at low altitude. Then, a current of air lifts it higher, and, as it rises, the water particle meets other water particles and gets bigger.
Still it rises, until it reaches the zones s where the temperature is very low, and freezes into a five sided crystal of ice. Still the crystal rises and collects more water which also freezes making the crystal so heavy that it begins to fall towards the Earth.
And as it falls, so it collects still more water becoming still bigger. Sometimes, it will join with other crystal to make a snowflake — which, once lands on Earth, can melt or accumulate with other snowflakes, according to the temperature at that time. And above certain altitudes, there is always snow because it always accumulates and never melts. The limit above which snow accumulates is called the boundary of perpetual snow and varies according to the latitude.
In the polar regions, the boundary of perpetual snow is situated at sea level. In the Alps, it is around 3,000 metres. On equator, this limit comes at around 4,000 metres.
