The Asymmetrical Story of a Snowflake

After living in the northeast for quite a while, you often see a lot of snow during the winter. There are so many questions that lie in this beauty of nature. Here we will address some of them.

Why are snowflakes hexagonal in shape?

Why are there different types of snow (e.g. powdery vs fluffy)?

snowflake_c_noaa
Visualization of a snowflake. Source: NOAA

First, it is necessary to understand how snowflakes begin their lives. Like all kinds of precipitation,  moisture needs to condense in the atmosphere, usually on some sort of air particle. The water molecules will naturally arrange themselves in the hexagonal crystalline structure- this is the precisely the reason for ice being less dense than liquid water, seen when ice cubes float in the liquid analog.

At the microscopic level, the hexagonal pattern results in some ice molecules protruding out at the vertices. As the frozen baby ice crystal falls through the atmosphere, water molecules are more likely to collect at these vertices. Gradually, the baby snowflake begins to develop its arms. However, the baby snowflake is unfortunate because its arms are not usually symmetric, contrary to how advertisements of snowflakes may depict them. In fact, most snow flakes are highly irregular because of minute varying water vapor around them. The small baby snowflake’s arms experience similar conditions to roughly look equal. The exact growth of the arms is highly dependent on the temperature and humidity around it. Here’s a video of a snowflake through its early development.

Throughout a snowflake’s life, like a human’s life, it encounters various environmental factors. As it falls due to the forces of gravity and the air resistance, the humidity and temperature constantly change, which influences the development of the snowflake. As a result, like humans, each snowflake follows a different path in life and as a result they become unique beings, each one distinct from another.

morphologydiagram
This diagram shows snowflake morphology at different temperatures and saturation levels. Both are important in determine snowflake shape and aggregation. Source: CalTech

Now depending on the temperature, the teenage snowflake decides whether or not to be social. If the temperature is around freezing, the snow will slightly melt and in doing so, meet up with other snowflakes and stick to them, forming a group of friends. These group of snowflakes can get fairly large as they finally land on the ground. These snowflakes eventually end their lives being mushed together to make a snowman due to their sticky nature.

On the other hand, if the temperature is quite cold and dry, the snowflake does not stick and remains primarily as a loner as it falls. It may meet with other snowflakes but they are easily offended and leave one another. These flakes eventually end their lives as the powdered snow at snow sports.

Regardless of what kinds of snowflakes you meet as they fall for you, consider the journey and hardships they have gone through before you just ignore them. Or eat them.

 

Sources:

https://nsidc.org/cryosphere/snow/science/formation.html

http://www.metoffice.gov.uk/learning/snow/how-is-snow-formed

http://www.its.caltech.edu/~atomic/snowcrystals/faqs/faqs.htm

http://www.noaa.gov/features/02_monitoring/snowflakes.html

Captivating Microscopic Time-Lapse Video Captures the Formation of Snowflakes

 

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