Are No Two Snowflakes Really Alike?
(and Other Amazing Snowflake Facts & Pictures)
by www.SixWise.com

Snowflakes -- bouncing in a chilly wind, settling on the tip of your tongue or flurrying outside an icy window -- are one of the simple pleasures in life.

But while simple in their beauty, the making of a snowflake, and the intricacies they contain, are actually quite complex.

How Snowflakes are Formed

Contrary to popular belief, snowflakes are not formed when raindrops freeze (this is called sleet). Snowflakes are formed inside of clouds, when water droplets freeze and become ice particles. Water vapor in the cloud gathers on the ice particle, causing it to spread into a simple hexagonal prism and then to sprout branches to form a more complex shape.

From here, though, snowflakes take on shapes of their own. The environment inside of a cloud (the temperature and humidity) is constantly changing, so much so that it changes the shape of the snowflakes, sometimes from one second to the next.

"A crystal might begin to grow in one manner and then minutes or even seconds later something changes (temperature or humidity), so it starts to grow in another manner. The hexagonal symmetry is maintained, but the ice crystal may branch off in new directions ... In the end, there are all kinds of forms that can arise: everything from prisms and needles to the familiar lacy snowflakes," says Howard T. Evans, Jr., an x-ray crystallographer and scientist emeritus at the U.S. Geological Survey.

It's the ever-changing environment inside of clouds that makes snowflakes unique. So is it true that no two snowflakes are alike?

"It is indeed extremely unlikely that two complex snowflakes will look exactly alike. It's so extremely unlikely, in fact, that even if you looked at every one ever made you would not find any exact duplicates," says physicist Kenneth Libbrecht, author of "Ken Libbrecht's Field Guide to Snowflakes."

35 Types of Snowflakes

While each snowflake may be unique, Libbrecht says there are 35 different types of snowflakes that you can recognize if you look closely. Some of the more common to keep an eye out for:

• Stellar Plates: Thin, plate-like crystals with six broad arms that form a star-like shape.

• Stellar Dendrites: Plate-like snow crystals that have tree-like branches and side-branches. This type of snowflake is often used as the shape for holiday decorations.

• Needles: Slender, columnar ice crystals that grow when the temperature is around 23 degrees F. They appear like tiny white hairs when they land on your clothing.

• Rimed Crystals: Frozen water droplets in clouds, called rime, sometimes collect on snowflakes. When the coverage is heavy, the snowflakes can take on the appearance of a tiny snowball.

• Fern-Like Stellar Dendrites: Similar to stellar dendrites, but with so many branches that they take on a fern-like appearance. These snowflakes are the largest ones out there, with diameters of 5 mm or more.

The Snowflake Man

Wilson Bentley (1865-1931) was a farmer who did pioneering work in photomicrography. In 1885, Bentley became the first person to photograph a single snowflake, and went on to capture over 5,000 snowflake images during his lifetime (without finding two that were the same).

In 1931, Bentley, who became known as "the Snowflake Man," published over 2,000 images in his unprecedented book, "Snow Crystals."

"Under the microscope, I found that snowflakes were miracles of beauty; and it seemed a shame that this beauty should not be seen and appreciated by others. Every crystal was a masterpiece of design and no one design was ever repeated. When a snowflake melted, that design was forever lost. Just that much beauty was gone, without leaving any record behind," Bentley said of his work.

The Largest Snowflake Ever?

The largest snowflake ever recorded, according to the Guinness World Records, was 15 inches wide and 8 inches thick. A man named Matt Coleman observed the snowflake in 1887 at Fort Keogh, Montana, and said the snowflake was "larger than milk pans."

However, official measurements of snowflake dimensions are not routinely taken, says the National Snow and Ice Data Center. The title may still be up for grabs, so head outside next time the snowflakes start falling and see what you can find!

Recommended Reading

How to Winterize Your Car ... and Your Brain for Winter Driving

12 Tips to Lower Your Heating Bill This Winter

Sources

Snowcrystals.com

ScientificAmerican.com

M&C Science & Nature

Wilson Snowflake Bentley

USAToday.com