When air rises, the water vapor cools at high altitudes and it condenses into droplets that accumulate and form clouds. These droplets remain suspended in the air because they are very small and light. When they become bigger and heavier, they fall as rain.
If the droplets cool down a lot, change into ice crystals. If the temperature in the layers of air is very low, the ice crystals in the clouds do not melt when they fall. Instead, they join together and fall as snowflakes.
Hail is formed when ice crystals in the clouds are pushed upwards by ascending air currents. The crystals get bigger until they are very heavy and fall.
But coming back to snowflakes, why do you think they have this hexagonal structure, which is unique for each one? Let's see.
In the video below we will learn how to make snow flakes for Christmas.