Unlocking secrets of the snowflake 'Range of benefits' : A study using a powerful microscope attachment promises help for farmers, hydroelectric companies, rescue teams, skiers and others.

January 11, 1996|By Dennis O'Brien | Dennis O'Brien,SUN STAFF

Skiers and farmers will be glad someday that William Wergin tested his new $100,000 microscope attachment on snow scooped from his car rather than on mold scraped from an orange.

His impulsive decision generated a first-of-its-kind study of snowflakes that scientists say could improve crop irrigation methods for water-strapped farms and predict avalanches in the Rockies.

Mr. Wergin, who heads the electron microscope laboratory at the Beltsville Agricultural Research Service, has collected 5,000 flakes from across the country to be photographed and stored in subzero temperatures in tubes at the agency just outside the Capital Beltway.

Why study snowflakes? Consider this:

* Eighty 80 types of snowflakes exist, but no two snowflakes are exactly alike. They range from the picturesque, six-pointed dendrites commonly seen on Christmas cards to the heavier needle- or column-shaped flakes.

A shovel filled with the heavy, wet needle- or column-shaped flakes can yield 50 times more water than the same shovel filled with the fluffier dendrites.

* The types of snowflakes that fall generally are determined by climate. The dendrites are more common in cold-weather states such as Alaska and Colorado and not as likely in Maryland, where more column and needle shapes fall.

* Blasts of cold air in states such as Colorado can change the shapes of snowflakes after they land, making them more rounded and slippery, a "ball bearing" effect that can cause avalanches in the West.

The Beltsville agency has "a whole new way to look at snow crystals, which could have a whole range of benefits," said Richard Armstrong, a climatologist and hydrologist from the University of Colorado in Denver who helped collect snowflakes in Colorado.

Farmers who choose which crops to plant based on runoff, hydroelectric companies, ski resorts and mountain rescue crews could all use information unlocked by Mr. Wergin's study.

Snow experts, ice physicists and hydrologists will discuss the Beltsville findings at the Western Snow Conference in Bend, Ore., in April.

The study began after Mr. Wergin received the instrument, a Low-Temperature Preparation Unit, from a British manufacturer Dec. 28, 1993.

Attached to an electron microscope, the cylindrical instrument allows examination of materials at 320 degrees below zero, the temperature of liquid nitrogen, a relatively inexpensive coolant.

Mr. Wergin said he scraped snow from the hood of his car and put it under his microscope, giving him the first view ever of a snowflake magnified 50,000 times.

"It was exciting, but at the time we didn't realize the implications of what we had," he said.

The importance of Mr. Wergin's finding was not lost on Albert Rango, a Beltsville hydrologist who has studied snowflakes for more than 30 years, and he teamed up with Mr. Wergin.

"The more we know about the snowflakes in a snowpack, the more we can tell about the amount of water it will produce," Mr. Rango said.

Collecting the flakes is cold and tedious.

Researchers wait for snowflakes to fall on chemically treated tissue slides, freeze them in canisters packed with liquid nitrogen and coat them with heavy metals so that they can be magnified and photographed.

A snowflake collection

The snowflake collection includes specimens from Fairbanks, Alaska; Loveland Pass, Colo.; Davis, W.Va.; and the Beltsville area.

Predicting water flow from snow melt dates back to the early 1900s, but the technology has changed.

For several years, the National Weather Service, the U.S. Natural Resources Conservation Service and the California Department of Natural Resources have used microwave readings from National Aeronautics and Space Administration satellites to provide snow melt forecasts.

"If farmers know they're in for a lot of water, they're able to plant high-yield crops that require a lot of water," Mr. Rango said.

Satellite images might pinpoint the depth of a snowpack, but they cannot adequately determine density, a key in predicting runoff, he said.

Mr. Wergin said that is what his study is all about: coming up with the densities of snowflakes that make up a snowpack.

"The size [of the flake] is important, and the shape. How these flakes pack together and interact and break down, that's what we're just beginning to understand," Mr. Wergin said.

Increased magnification

Up to now, he said, the study of snowflakes had been limited to traditional light microscopes, which can magnify images up to 100 times. By contrast, the electron microscope can magnify a snowflake up to 50,000 times.

The $250,000 microscope also can photograph flakes from different angles, which allows scientists to use a stereoscope to view the flakes in three dimensions.

Mr. Armstrong, the Colorado scientist, said such technology has allowed scientists to see a snowflake in enough detail to enable them to verify what had been only scientific theories about their composition.

"We're able to see structures in these flakes that we've never really seen before," he said.

Baltimore Sun Articles
|
|
|
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.