English novelist J. B. Priestley wrote that “the first fall of snow is not only an event, it is a magical event.” His words epitomize the beauty of the white billowing frozen drops of water falling from the sky. Children in colder climates can’t wait until the first snow day, that extra day away from school, when snowflakes fill the air. Children in warmer climates envy them, wishing for a freak snowstorm to hit. Snowflakes, though, form from complex processes and have intricate details upon close examination.
How Snowflakes Form
Snowflakes are forms of precipitation that start as ice crystals the size of a speck of dust in the sky. As these specks of dust fall, they join together to build a larger ice crystal consisting of six arms. According to the National Oceanic and Atmospheric Administration, the six-armed snowflakes develop because “they reflect the internal order of the crystal’s water molecules as they arrange themselves in predetermined spaces.” This process is called crystallization.
Why Snowflakes Have Different Shapes
Atmospheric conditions determine a snowflakes shape. In general, snowflakes with long needle-like crystals form at 23 degrees F, while flat plate-like crystals form at five degrees F, according to the NOAA. Despite these basic similarities, they all look different under a microscope. Though all water molecules consist of two water molecules, they come in a variety of different structures. In addition, microscopic changes develop because they fall from the sky at different angles and are subject to changing atmospheric conditions like humidity.
Scientists have tried classifying snowflakes for centuries. In 1951, the International Association of Cryospheric Sciences classified snowflakes into 10 basic shapes. The organization still keeps annual tabs on international snowfall. The IACS categorize snowflakes as plates, stellar crystals, columns, needles, spatial dendrites, capped columns, irregular particles, graupel (soft hail), sleet, and hail. Among the 10 basic categories are subgroups of snowflakes. Though the IACS classification is widely accepted, Ukichiro Nakaya of Japan took pictures of snow crystals and studied them under a microscope.
Is Snow Really White?
Snowflakes appear as fluffy, white crystals falling from the sky. They appear white because snow absorbs visible sunlight, which causes the coloring. Snowflakes can, however, absorb other colors under different conditions. The National Snow & Ice Data Center says snow sometimes looks blue, especially in deep crevasses. This occurs because it travels below the surface of snow. Industrial elements like coal dust turn snowflakes black or gray. Natural features like red clay turn snowflakes pink. This occurs because of dirt blown into the sky.
Snowflakes fall to the earth, blanketing it with white snow that brings visions of fun for many children. Though they look like simple pieces of frozen water falling from the sky, snowflakes, like people, are all different. They have similar characteristics but are different in appearance and are affected by temperature and location. Snowflakes have inspired writers and scientists to explore their beauty and intricacies.