from the presurfer
The video tracks formation of snowflakes from their origins in bits of dust in clouds that become droplets of water falling to Earth. When the droplets cool, six crystal faces form because water molecules bond in hexagonal networks when they freeze.
As snowflakes continue to develop, the branches can spread, grow long and pointy, or branch off into new arms. As each snowflake rises and falls through warmer and cooler air, it thus develops its own distinctive shape.