Technology helps keep slopes open
Glen Heinrich-Wallace RECORD INTERN
Any number of things must come together for a ski resort to be operational: the lifts have to run, the lodges have to be open, and most importantly, there must be snow on the slopes. Hanging in a prominent position on the wall in the office of Brian Schadolc, the Slope Maintenance Manager for Park City Mountain Resort, is a picture that serves as a reminder that this last is no longer entirely in the tempestuous hands of Mother Nature. The picture shows PCMR in full spring verdure save for a line of white stretching down Payday and First Time. It is dated November 1995.
"Some years we’re skiing on manmade stuff for a couple of weeks," he said. "We want to ensure that there’s a two-and-a-half to three-foot base when the resort opens."
As in ’95, this isn’t always easy. The mountain officially begins its snowmaking operation on Oct. 15, a date chosen for budgeting reasons, and scrambles to get things ready for the opening a month later. The snowmaking team will work in two 12-hour shifts until the operation stops in mid January. Weather permitting, the snow guns run 24/7 for four months.
"It’s the most fun I’ve had working on the mountain," said one employee, the sarcasm seeping through his thick Australian accent, "and I’ve had a couple of jobs."
According to http://www.about.com , the first manmade snow was produced by accident in a Canadian laboratory where researches were trying to replicate other natural weather conditions. The scientists were spraying water outside of the intake valve to a wind tunnel but discontinued the practice when they grew tired of shoveling snow out of the tunnel. The researchers published their findings but did not pursue the matter any further than that.
The first patent for a snowmaking machine was issued to Wayne Pierce, who worked in ski manufacturing, in 1954. His machine, a testament to tinkerers, was thrown together with a paint spray compressor, a nozzle, and some garden hose. Since then, there have been many more patents, but the basic idea has remained the same, states http://www.about.com; to mix air and water and release them into a cold environment.
PCMR runs three different types of snow guns: SMI fan guns, Ratnik ground guns, and AKD tower guns. Fan guns produce the largest amount of snow, but because of their size, are difficult to transport. Ground guns produce less snow but can easily be dragged from one area to another with a snowmobile. Tower guns blow their snow from a raised position that spreads the snow over a large area. All of the models produce snow by blasting a stream of water into tiny droplets with a stream of compressed air, which then blows the newly form droplets out of the nozzle where they, hopefully, will freeze before reaching the ground.
There are three factors that influence how effective snowmaking is: how long it takes for water droplets to reach the ground, the size of the droplets, and the "nucleation temperature" of the droplets. Raising the elevation of the gun, by placing it on top of a tower for instance, helps to increase the time it takes for the water to reach the ground. Because the droplets have farther to fall, there is a greater chance of more of them freezing. PCMR has tower guns along its high-traffic runs, like Payday.
The size of the water droplets is important because of thermodynamics. You can easily observe this in your own kitchen by putting a small cup of water and a large pot of water in your freezer at the same time. The water in the cup will freeze before the water in the pot. Similarly, a small drop of water will freeze faster than a large one. The third factor, nucleation temperature, is more complicated.
"There’s something called the ‘wetbulb temperature,’ which is a combination of humidity and regular temperature. I have a chart," said Schadolc pointing a piece of paper tacked to a board beside his desk, "that tells me if I can make snow under certain conditions." For example, the wetbulb temperature is the same at 28( F with 10 percent humidity as at 20( F with 90 percent humidity.
"The rule of thumb is that for every 10 percent increase in humidity, you take one degree off," said Schadolc.
While this might seem odd, there is something else involved in snowmaking that is much stranger.
Scientifically, the atoms in a substance at a high temperature are moving more quickly that those at a lower temperature. This is why when water is chilled it turns to ice (a solid) and when it is heated it turns to steam (a gas). Most people think that water freezes at 32( F, or 0( C, but this is not necessarily true. Pure water can be "super-cooled" to as low as -40( F before it freezes. However, it will not melt until the temperature rises above 32( F.
The reason for this is that pure water must drop to a low temperature for the first crystal or "embryo" of ice to form. After the first of these is formed other water molecules will quickly follow suit. Fortunately, most water is not pure.
Foreign chemicals in water can act as "embryos" which allows the water to freeze at a warmer temperature. If a molecule of, say, calcium is present in a drop of water, it will freeze between 15( and 20( Fahrenheit. In most water used in snowmaking, some droplets have these "high-temperature nucleators" while others do not or have "low-temperature nucleators." Because of this, when the droplets are all blown out of the nozzle together, some freeze into snow and others remain drops of water.
Snowmakers want to make as much of the water they pump into their guns into snow as possible. Because of this, many will mix some chemicals into the water. The most common of these is Snomax.
"Everybody uses it," said Schadolc. "If you’re using the stuff, you’re gonna make more snow."
According to York Snow, Inc., which produces Snomax, the chemical is a protein derived from the common bacteria Pseudomonas syringae, and is the most efficient high-temperature nucleator used in snowmaking. It has been subjected to numerous tests to determine whether or not it has negative effects on mountain ecosystems.
Both the U.S. Department of Agriculture and the U.S. Forest Service have cleared Snomax domestically. It has also passed inspection in Australia, Canada, Finland, France, Italy, Japan, Norway, Sweden, and Switzerland. One Canadian study claimed that if all the ski resorts in Canada used Snomax, the amount of the chemical released would not exceed what could be found in 100 leaves on a tomato farm.
Last year there was some concern raised over a study being run by the University of Utah. However, in a release published on Oct. 13, 2005 by the Vice President for Research, the University stated that while "early studies showed antifungal activity of Snomax under laboratory conditions. The laboratory conditions used in the study were not consistent with the manner in which Snomax is used, and any extrapolation of the observed results to conditions present during typical snowmaking activities is inappropriate."
"I don’t see how it could hurt anything," said Schadolc, "we just use a tiny bit in a huge amount of water."
Some people claim that Snomax not only makes more snow but better snow. However, Schadolc is skeptical. "Personally, I can’t tell the difference. Our standard is that we should be able to pack and then crumble any snow we make," he said.
One thing he is sure of is that snowmaking, and Snomax, help keep the mountain open. "It ensures we’ll open on time and have ski-able terrain until we close," he said. "I don’t think you can put a price on that."
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