Snow

Snow is one of winter's greatest wonders. Snowflakes are ice crystals that form inside clouds when the temperature is below freezing. Each snowflake starts as a tiny speck of dust or pollen. Water vapor freezes onto it, forming a beautiful crystal. Snowflakes always have six sides, but no two are exactly alike.

How Snow Forms

Inside a cloud, water vapor freezes onto tiny dust particles. As the ice crystal falls through the cloud, more water vapor freezes onto it, making it bigger. The crystal grows into a snowflake with six branches. The shape depends on the temperature and moisture in the cloud. When the snowflake is heavy enough, it falls to the ground.

Snow on Earth

About 12 percent of Earth's surface is covered in snow and ice year-round. Fresh snow is mostly air, which is why it is so fluffy and light. Snow acts like a blanket, keeping the ground underneath warmer than the air above. Many animals and plants depend on snow cover to survive winter.

Fun Facts

• The largest snowflake ever recorded was 15 inches wide and 8 inches thick, found in Montana in 1887.
• Snow appears white because the ice crystals reflect all the colors of light.
• One inch of rain is equal to about 12 inches of snow.

Did You Know?

In some very cold places, snow can squeak when you walk on it! This happens when the temperature is below about 14 degrees Fahrenheit. The ice crystals are so cold and dry that they do not melt when pressed together. Instead, they break and rub against each other, making a crunching or squeaking sound.