- The Washington Times - Wednesday, December 20, 2006

Jay Roberts stands underneath the spray of snow coming from a snow gun, his right arm extended. It is a crisp, otherwise snowless day at Wintergreen Resort in the Blue Ridge Mountains southwest of Charlottesville.

He looks out at two to three feet of snow on one of the resort’s 25 trails. Snow sticks to his sleeves, indicating its high water content. The wet, dense snow will be used for the base layer and topped with a dry, fluffy snow that does not stick to clothing.

Mr. Roberts, vice president of mountain operations for the Central Virginia ski resort, uses his sleeve to demonstrate how the resort used to monitor snow quality with a traditional, or manual, snow-making system.

“You used your sleeve as an indicator. How it was sticking to your clothing indicated the quality of snow you’re making,” Mr. Roberts says over the roar of the snow guns as they shoot snow 50 feet in the air, preparing the resort for opening day earlier this month.

“It was very inaccurate,” he says.

Before the 2002-03 and 2003-04 seasons, when the resort became fully automated, a full-time staff of 16 snow makers had to check periodically and adjust the snow guns by opening and closing the water hydrants that supplied them with water, Mr. Roberts says. The snow makers made the adjustments based on air temperature and humidity, he says.

Today, six snow makers can do the same job in less time. They can get the York Snow computerized snow-making system up and running in less than 15 minutes instead of taking 1 hours, and they can use computers to do the monitoring. The cost to Wintergreen for the upgrade was about $5 million.

“It’s not cheap. That’s the major reason people don’t invest in it,” Mr. Roberts says, “but it makes better snow, and lots of it.”

Ninety percent to 95 percent of snow-making areas in North America are operated manually, says Rich Brown, director of York Snow, a company in Rochester, N.Y., that sells and services snow-making equipment.

At Wintergreen, Mr. Roberts opens the lid of a galvanized pipe sunk into the ground to point out the inner workings of one of the resort’s 400-plus air-water snow guns. Two underground hydrants connected to pipes bring water and compressed air to the gun. Cables send information to a central computer in the resort’s compressor control building about weather conditions, water usage and snow production for constant monitoring.

“Computers make the adjustments for you. It means the quality is much better because the adjustments are made constantly, and they’re more precise,” Mr. Roberts says.

Snow guns make snow by combining cooled water and compressed air inside the aluminum body of the gun, then releasing the mixture into the air, he says.

“The water obviously makes the snow, and the compressed air breaks down the water into billions of water droplets. It also serves to throw out the snow over the trail,” Mr. Brown says.

The air-water mixture rapidly expands as it goes from the compressed environment and is released into the atmosphere, Mr. Roberts says. The more time the air-water mixture has to fall to the ground, the more time it has to freeze.

Snow that falls naturally collects dirt, dust and other small particles that act as agents to bring the air and water together for the snow to form. Wintergreen Resort uses a water additive called Snowmax, a product York Snow sells, to aid in the freezing process.

“That product goes into the water and provides a freezing site for every drop of water,” Mr. Brown says.

Water freezes when the water crystals can align around particulate matter, or nucleators, whether they are natural or man-made, Mr. Brown says. The water will not align in a six-sided ice crystal without something to which it can attach, he says.

A snowflake is an agglomeration of ice crystals, says Vlad Sadtchenko, assistant professor of chemistry at George Washington University.

“You don’t get beautiful snowflakes from a snow gun — more like a rounded crystal,” says Mr. Sadtchenko, who holds a doctorate in chemical physics. “With man-made snow, it’s much more dense than the naturally occurring snow.”

Snow can be made in temperatures up to 34 degrees, but lower temperatures are better for producing snow more quickly, Mr. Roberts says. Warmer temperatures require additional energy to cool the air-water mixture and, along with the level of humidity, can limit the amount of water that can freeze, he says.

“There comes a point when the air gets so saturated with water, it can’t take any more. The less humidity, the better,” Mr. Roberts says.

This year, Bear Creek Mountain Resort near Macungie, Pa., installed 25 automatic snow guns in addition to 70 manual snow guns to improve production efficiency and produce more snow in less time, says Mark Schroetel, general manager of the resort.

Bear Creek uses airless, or fan, snow guns, which are more efficient in marginal temperatures than air-water snow guns, Mr. Schroetel says.

“The air acts as a propellant and separates the water into finer particles, and after it’s propelled from the head of the gun, it drops to the ground as frozen ice crystals. It does cool as it expands, but not to the ambient air temperature,” he says. “That’s why the fan snow gun works better.”

Fan snow guns have a barrel with a rotating fan that breaks up the water stream coming from the hydrant and throws it out over the trail, Mr. Brown says.

The fan guns cost $18,000 to $25,000 a unit, compared to air-water guns that cost $800 to $1,500 each, but the air-water guns are more expensive to operate and require the investment in compressors, he says.

Bryce Resort in the Shenandoah Valley in Basye, Va., installed 30 automated air-water snow guns this year and plans to become fully automated within the next five years.

Air-water snow guns are “a lot easier to start up and shut down,” says Ryan Locher, mountain manager for Bryce Resort. “You get better quality snow, because if the temperature warms up, we can get the guns turned off quick enough so the snow doesn’t get wet.”

In West Virginia, almost 1 percent of Snowshoe Mountain’s more than 400 snow guns are automatic.

“I’m waiting until the technology becomes a little more refined and the pricing comes down” before purchasing the automatic technology says Ed Galford, vice president of operations at the West Virginia resort.

Once that technology becomes more affordable, “it will be the wave of the future, no doubt about that,” he says.

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