Clouds of crystal

Of all of Mother Natures works of art, few can rival the beauty and wonder of a snowflake.

WINTER is still only at its midpoint, and already, New York City is measuring its snowfall for the year in feet. Trying to imagine the number of individual snowflakes in the piles of white stuff that have blanketed the city so far would be a little like trying to count the ocean drop by drop. Yet, every inch, foot, and blizzard of snow is made up of a countless number of tiny, individual snowflakes, each one unique.

As water evaporates from the Earth into the air, it forms clouds. When the temperature drops below freezing 0 degrees Celsius, 32 degrees Fahrenheit the water is forced out of the air particles containing it and freezes from a liquid into a solid state. These are snow crystals. Snow is basically a type of ice.

The shape and structure of snowflakes are determined by many environmental factors the temperature they formed at, the dust and air pollution they came in contact with, the movement of air currents and humidity. Temperature and humidity levels produce specific types of snow crystals. Yet, despite the infinite shapes and sizes these many factors can produce in a snowflake, scientists have been able to identify distinct categories of snowflakes and have even devised a system for classifying snowflake types.

The 1951 International Commission on Snow and Ice established a classification system identifying seven types of snow crystals: plates, stellar crystals, columns, needles, spatial dendrites, capped columns and irregular forms.

In 1954, the Japanese physicist Ukichiro Nakaya took the study of snow crystals a step further, identifying 41 distinct forms of snowflakes. He artificially reproduced snow crystals in his laboratory to determine how the different types of crystals resulted from different environmental conditions. In 1966, meteorologists expanded upon Nakayas system, breaking out snow crystals into 80 different forms.

The most basic form of a snow crystal is a hexagonal (six sided) prism. Snowflakes are usually symmetrical, but can by asymmetrical. They are multifaceted, meaning they are three-dimensional and have many sides and faces. These many surfaces reflect light in various ways that the human eye cannot detect. Because of this, snow which, like ice and water is actually transparent — appears to be white to the human eye.

So, the next time a snow storm blows into New York City, consider the incredible journey each one of those snowflakes has made from its humble beginning as a drop of water in a river, ocean, or breath of human exhalation, through the atmosphere into a cloud, where it crystallized into one of natures great miracles of beauty before making its decent back to earth, where it will eventually start the process all over again.

Picture Above: New Yorkers have had plenty of opportunities to catch snowflakes on the tongue this winter.

New York Post, December 15, 2010
Written by: Robin Wallace