While we may not think of anything inherently beautiful about a single drop of water, most people find that when water molecules in the air freeze and fall to the ground, the water becomes something extraordinary.
What turns that wet mess of hydrogen and oxygen atoms into a crystal? How does an individual snowflake actually form? Well, way up in the sky, there are microscopic dust and pollen particles (yes, pollen is still flying around even in the winter!) that water molecules latch on to. When the temperature in sky falls enough, the water droplet freezes and becomes too heavy to continue floating around in the sky. Since water expands as it freezes, it forms a small, ice crystal around the dust or pollen. As that droplet falls it grows into the beautiful, six-sided crystal that you might have the chance to see on the ground, your windshield, deck railings, or even your eyelashes (cue Sound of Music’s, “These are a Few of My Favorite Things.”)!
Two main things impact the way that a snowflake “grows”: Temperature and Humidity. These atmospheric conditions will change during the snowflake’s journey from sky to ground, thus creating little arms, gaps, points, and edges on the snowflake.
The colder it is, the simpler the snowflakes look. These cold weather (and by cold weather, I mean in the negatives!) snowflakes may not appear to even have arms. Researchers have also found that the drier it is, the simpler the snowflake is. Combine very cold temperatures with very dry conditions and you can get some atypical looking snowflakes ranging from a hexagonal plate to a simple column! The warmer it is, and the more humid it is, the more intricate the snowflake becomes! Snowflakes formed in warmer, wetter conditions may be needle-like and have clearly defined arms.
As atmospheric conditions change during the snowflake’s journey, the snowflake structure will change, thus creating the gaps and points on each of the six arms. Water vapor latches on to the snowflake and freezes quickly. Then new water vapor attaches at a different atmospheric condition and freezes in a different way! This is also the reason that snowflakes are unique. Every one falls at a different rate due to the dust or pollen particle size and weight and falls when the temperature and humidity is ever so slightly different. While it is possible that two snowflakes could have the same shape, the odds of that happening are so huge that scientists have yet to discover two of the same. Watch a snowflake actually form to see how the edges and gaps are created by clicking here!
In 1951 scientists came up with a classification system that categorized 10 different snowflake shapes. These shapes, again, are determined by the atmospheric conditions of temperature and humidity, so the simply, flat snowflakes and the intricate, obviously armed snowflakes are rarely found in the same geographical location. Check out the snowflake shape categories and some snowflake research here!
While winter may not be everyone’s favorite season, we can all agree that water to snow formation is incredible! To check out some fascinating snowflake photography, learn more about snow structure, or to discover how individual snowflakes come together, click on these great links!