How Are Snowflakes Formed?

Snowflakes get their unique shapes from the conditions in which they form and grow in the atmosphere. 

The shape is determined by temperature, humidity, and how it moves through the cloud. 

  • Icy Crystal Formation A snowflake starts as a tiny, invisible dot of water vapor in a cloud. When it gets really cold, the water vapor begins to freeze and becomes a tiny ice crystal.
  • Growth of SnowflakesAs ice crystals fall through the cloud, they encounter different temperature and humidity conditions, which cause the ice crystals to grow by adding more water molecules to their structure. 

Why Are Snowflakes Symmetrical?

Snowflakes are symmetrical because of the way they are built. Symmetry means that one side of an object looks the same as the other side. 

A snowflake usually has six sides, each looking like a mirror image of the other. 

  • Water molecules are made of two hydrogen atoms and one oxygen atom (H2O). 
  • When these molecules freeze, they arrange themselves in a hexagonal pattern
  • As the snowflake grows, this pattern repeats on all six sides.

Snowflakes And The Water Cycle

Snowflakes play a crucial role in the Earth’s water cycle.

  • Precipitation: Snowflakes are a form of precipitation. When water vapor in the atmosphere condenses into ice crystals and grows large enough, they fall to the ground as snow. 
  • Storage: In colder regions, snow accumulates on the ground over time, forming snowpack. This snowpack is a natural reservoir, storing water until it melts in warmer weather. 
  • Runoff: When snow melts, the water flows over the land and eventually returns to the oceans, completing the water cycle. This runoff is crucial in providing water for plants, animals, and human populations.
  • Climate Regulation: Snow and ice also play a role in regulating Earth’s climate. They reflect sunlight back into space, which helps to cool the planet. Changes in snow cover and ice affect global climate patterns.

Fun Facts

Here are some interesting facts about snowflakes:

  • Snowflakes float down at around 1.5 miles per hour, taking about an hour to reach the ground.
  • Snowflakes are not white. They are translucent.
  • While 6-sided snowflakes are the most common, 3-sided and 12-sided snowflakes are other possibilities.
  • The largest snowflake ever recorded measured 15 inches wide and 8 inches thick. It fell in Fort Keogh, Montana, in 1887
  • Wilson Bentley, a farmer from Vermont, was the first person to photograph a single snowflake in 1885. He captured over 5,000 images of snowflakes during his lifetime.


Let’s quickly recap what we learned about the science behind snowflakes:

  • What does a snowflake start as? Ice Crystal
  • What are the three factors that determine the shape of a snowflake? Temperature, humidity, and how it moves through the cloud
  • How many sides does a snowflake usually have?  6 Sides
  • In which phase of the water cycle does a snowflake form? Precipitation
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