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This information about snowmaking is courtesy of the American Skiing Company.
At the simplest level, snow guns are simply nozzles in which air and water meet. The water, of course, is the raw material from which snow is made. The air has two purposes: to shatter the stream of water into tiny droplets, and - along with water pressure - propel those droplets into the atmosphere. To accomplish this task, there are two basic types of snow guns: "airless" and "air/water." How "airless" guns work Airless guns often resemble large oil drums, and are generally mounted on permanent towers or on sleds towed behind a snow cat. Airless guns spray water out of small nozzles not unlike the spray valves homeowners attach to garden hoses. The nozzles ring a large, electrically - or gasoline - powered fan in the center of the "barrel". The fan disrupts the jets of water into small droplets, and propels them into the air. Airless guns are cheaper to operate than air-water guns, given that no air compressor system is required. Additionally, rather than constructing a second pipe to transport compressed air, a ski area instead needs only to install a heavy-duty electrical line along the side of a trail. There are some significant disadvantages, however. While airless guns can produce an impressive amount of snow, their size makes them very difficult to move around. And they're expensive, too - airless guns typically cost $10,000+ per copy, exclusive of the cost of the vehicle or tower. How "air/water" guns work Air/water guns, the type favored by most large-scale snowmakers, are nozzles in which a stream of water is internally interrupted by a jet of compressed air. There are currently more than a dozen variants on the market. Early air/water guns were ingeniously assembled from stock plumbing fixtures. By today's standards, they were inefficient - and could produce quality snow only in extremely cold conditions. In the mid '70s, as snowmaking became more common, guns became more carefully engineered. Still, they were a long way from today's guns in their efficiency, ease of operation and consistency in snow production. Today's snow guns have markedly better performance characteristics than those available even as little as ten years ago. But there are still variations. Some can produce more snow than others; some work well at very cold temperatures, but poorly at warmer ones (during which time ski areas are most likely to need to make snow). At a cost of $300 to $1500 per copy, exclusive of hoses, air/water guns are also very expensive. Many resorts still use older equipment, and inventory only as many guns as their air and water systems can supply at one time. Even ski resorts with a large inventory of guns frequently have a mix of make and vintage. Since the performance characteristics of each type of snow gun varies, crews must learn to utilize different guns - often right next to each other. This often leads to inconsistent surface conditions. As a result, American Skiing Company resorts inventory only one or two different gun types, and each resort possesses enough guns to ensure that snow can be made when and where needed. Crews do not lose valuable time moving guns. An ideal gun is simple, with minimal chance for freeze up; it throws snow a long distance, ensuring good coverage on wide trails; it works well over a wide range of temperatures and produces snow crystals of uniform size. It is energy efficient, requiring little compressed air (which also makes it quieter). Finally, an ideal gun is small, lightweight and easy for snowmakers to move, enabling crews to cover trails evenly. The American Skiing Company has been on the leading edge of snow gun technology for nearly a decade. The company has developed a new gun that is small, lightweight, and efficient. Its unusual design wraps the air chamber in the gun with water, minimizing the likelihood that moisture will condense in the air chamber and impede air flow. Finally, it produces consistently - sized water particles, necessary to create consistent, powdery snow. The company is continuing its gun research, attempting to develop ways to increase snow depth by creating snow crystal structures more typical of natural crystals.
So Just What is Great Machine Made Snow? Environmental Aspects of Snowmaking
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