Spectacular Nature: That thing called 'Snow'
A dog stands on the frozen bank of the Yenisei River 40 km from the Siberian city of Krasnoyarsk.
Snowflakes start as ice crystals that are the size of a speck of dust. When the crystals fall they join up with other crystals to form a snowflake. The size of the snowflake depends on how many crystals hook together.
Like a fingerprint, every snowflake has its own unique shape and is different from all other snowflakes. All snowflakes have six sides.