Why does snow fall?
Snow forms when water vapour inside a cloud freezes into tiny crystals. The water vapour usually crystallizes around a tiny dust particle called a nucleus, and the snow crystal continues to grow. Crystals of snow clump together to form snowflakes, which fall from the clouds. As many as 100 snow crystals group together to form a 2.5 cm snowflake. Snow crystals are very beautiful in form. They are flat and six-sided, and can grow in the shape of elaborate stars.
Picture credit: google
What is the snow line?
The snow line marks out the area above which a mountain is permanently covered with snow. Because it gets colder as you move higher up, the snow will never thaw on a high mountain. However, the snow line moves higher up during the summer when some of the snow melts. The snow line is close to ground level in cold regions, but it is very high near the Equator where the air is much warmer.
Picture credit: google