The Science of Snowflakes

PROVIDENCE, R.I. (WLNE) — The formation of a small snowflake is anything but simple, from inside the cloud all the way to the ground.

When water vapor freezes into a crystal around a particle of dust, it forms a snowflake.

The growth of snowflakes is known as crystallization, which is the same process that occurs when any substance changes from a liquid to a solid state.

When snowflakes form, they all have six sides, a fate determined at the molecular level.

Six water molecules latch together in below-freezing temperatures, it creates a hexagon.

This hexagon forms the core of the primary crystal and lays the foundation for the six branches of a snowflake.

There are points at the corners of the six sides that attract more water vapor than the rest of the hexagon.

As the six points grow, they can catch more water vapor and grow faster than the rest of the snowflake, creating a positive feedback loop.

As the snow crystals grow in the cloud, they become heavier and eventually fall toward Earth.

It takes about an hour on average for a snowflake to reach the ground.

As the snowflake moves through the cloud and falls to Earth, it is exposed to changing temperatures and humidity, which determines its shape.

When the humidity is high, more elaborate, branched crystals grow.

On the other hand, simple prisms grow when the humidity is low.

Temperature determines if the crystals become a flat plate, a long column, or a prism shape. Big snowflakes form in warmer temperatures while colder temps make tiny crystals.

On average, 10 inches of snow melt down to about an inch of water, but not all snow contains the same amount of moisture.

This moisture content makes the difference whether shoveling out becomes a workout.