Modeling Snowflakes in Wintry Wisconsin

December 17, 2010 

Scientists have developed a computer program that models the growth principles of snow crystals. Using mathematical equations repeated billions of times, the program creates snowflakes that look like they tumbled right out of the clouds.

In real clouds, snow crystals (crystals of ice) form in the shape of hexagonal prisms. As they grow, branches sprout from the corners, creating ever more complex shapes. Conditions such as temperature and humidity in the atmosphere also influence their shapes.

"We were able to make a mathematical model that captures these detailed features and all kinds of details that most people have found so mysterious," said mathematician David Griffeath (University of Wisconsin-Madison).

Griffeath, working with Janko Gravner (UC Davis), successfully modeled snow crystal growth. "The spines, they're three dimensional features that our model captured beautifully," he explained.

Watch a slideshow of Griffeath and Gravner's computer-modeled "snowfakes".

Their model may also have a practical application. It could allow researchers to better predict how snowflake types affect the amounts of water reaching the earth.

The MAA, AMS, and the American Meteorological Society contributed to the information in this December 2010 DBIS report.

Source: Discoveries + Breakthroughs Inside Science (December 2010)

Image of computer-modeled"snowfake" via University of Wisconsin-Madison