Field guide to snowflakes

Here I am, walking to work one day, excited about falling snow and a crisp winter day outside. And then boom! Got hit by a snowflake right in the eye! No worries, I thought to myself, if only I could get a closer look. If you feel like that too, here is a field guide to snowflakes.

A clever chap, Kenneth Libbrecht, did some extensive research in this area, and suggests, that the best time to see a variety of snowflakes (i.e.  more types) is when the temperature outside is either minus five or around 10-15 degrees.

morphologydiagram

 The life of a snowflake begins with water vapour in the air.  In the winter, snow-forming clouds are still mostly made of water droplets, even when the temperature is below freezing.  If a particular droplet freezes, it becomes a small particle of ice surrounded by the remaining liquid water droplets in the cloud.  The ice grows as water vapour condenses onto its surface, forming a snowflake in the process.

I think snowflakes are fascinating. With so many different types, shapes and sizes, they never fail to amuse.

Let’s start with the most basic type, simple prism.

simple prismA  prism is the most basic snow crystal.  Depending on how fast the different sides grow, prisms can appear as different shapes.  Simple prisms are usually so small, they can barely be seen with the naked eye.

Stellar plates are a common type of snowflakes (and are very pretty indeed!). These snowflakes form when the temperature is near -2 C (28 F) or near -15 C (5 F).

stellar platesDendritic means “tree-like”, so stellar dendrites are snowflakes that have branches and side branches.  These are fairly large crystals, typically 2-4 mm in diameter, that are easily seen with the naked eye. These snowflakes are the most popular snow crystal type, seen in holiday decorations everywhere.

stellar dendritesIf the branches of stellar crystals have so many side branches and look a bit like ferns, they are called fernlike stellar dendrites.  These are the largest snow crystals, often with diameters of 5 mm or more.

fernlike stellarNeedles are slim, columnar ice crystals that grow when the temperature is around -5.  These snowflakes look like small bits of white hair (eww) .

needlesAnd the prettiest of all is a 12-sided snowflake. These crystals are quite rare, but sometimes a snowfall will bring quite a few.

12 sidesLast, but not least, is artificial snow, found at the ski fields.  This type of snow is made of frozen water droplets, with none of the elaborate structure found in real snow crystals.

fake snow

If you would like to learn more, here is the link to K. Libbrecht’s  book, available on Amazon.

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