There's No Business
Like Snow Business

Snow flakes may be the world's most innovative seasonal marketing campaign. Advertisers would be hard pressed to generate the sales and scientific research sparked by snow flakes—winter's one-of-a-kind ads. Snow is always falling somewhere in the world, and scientists and engineers are amassing a wealth of winter knowledge: the science of snow and skiing.

After years of dissecting, studying, and photographing snow flakes, Charles Knight has never given the science of snow the "cold shoulder." (Knight's striking snow flake photos are available to journalists.) Instead, he works to understand snow on a molecular level. Far above the earth, "supercooled" drops of water form clouds. The few drops that contain "ice nuclei" freeze and begin to grow. "Growing molecule by molecule, the complex shapes that we associate with snow crystals form in clouds," says Knight. When these crystals aggregate with each other, snow flakes form.

When winter resorts run short on "the real stuff," they manufacture snow by spraying water into the cold air. Knight explains the process.

"The water hits the ground as sleet, or ice pellets, not 'snow' to an atmospheric scientist. Anyone standing under the spray from a snow machine wouldn't call it snow either."

Without special provisions, the water shot from snow guns would form a ground layer of ice that could turn slopes into vertical skating rinks.

"Artificial ice nuclei, prepared from cultures of bacteria, are commonly added to the water sprayed from snow machines to facilitate mid-air freezing," Knight says.

Advances in snow making are complemented by a decade of breakthroughs in ski design. This burst of innovation follows a 100 year period without major design advances. At the AAAS Annual Meeting, Bard Glenne, an engineer and former ski racer, will describe innovations made in the last ten years and predict advances for the next ten years. "Improvements in ski design will make skiing easier to learn," he says.

From the slopes back to the microscopes, snow science contributes to basic science and our understanding of the natural world, according to John Wettlaufer. Science at the thin "quasi-liquid film" at the surface of ice helps scientists explain the origins of arctic "rock circles" and lightning. The research that led to an understanding of ice's watery surface layer also applies to condensed matter in general.

From double black diamonds to quantum mechanics and pollution, snow and ice will keep scientists and the public engaged long after Frosty has melted for the year.

—Daniel Kane

17 February 2003