The main ingredients needed to make snow are water and cool temperatures. The process is greatly helped if a nucleator is mixed into the water supply. Water contains ingredients that can act as nucleators, but increasing the amount of them ensures more water droplets will freeze before reaching the ground. Snowmax is one of the most popular nucleators used. This natural protein attracts water molecules.
Snow guns that produce water droplets by combining cooled water and compressed are found on ski slopes. Two different hoses attached to the snow guns and attached to air and water hydrant stations are connected to two different lines that run under the snow or underground. The compressed air atomizes the water, blows the water droplets into the air, and cools the water droplets as they blow into the air.
When air is compressed, the air particles cannot move around as much. When releasing the air particles, air particles spread out. All of this means the particles are using more energy, absorbing the heat from the area around them, and cooling the air around the water droplets.
Another type of snow machine sometimes used is an airless snow gun. This gun uses simple nozzles to atomize the water into a fine mist. The water droplets are blown into the air by a powerful fan. The main advantage of this design is that there is no need for compressed air, just water and a power source.
Changing water from a liquid to a solid uses a lot of energy, but is an important step in snowmaking. Removing the water’s heat of fusion, which is the large amount of heat energy required to change ice into liquid water at 32F, is very important. If it is cold enough, actually below freezing, the natural conditions outside will be sufficient for freezing water. If it is not cold enough then cooling units will be needed to speed the freezing process along.
Snow gun towers, used to give the water enough time to freeze before falling to the ground, are sturdy poles that elevate the snow gun above the slope allowing the snow to fall from above as it would naturally. This set up is also less disruptive to skiers.
Snow-grooming equipment is often used to disperse accumulated piles of manmade snow along the trail where it is needed. Snow-grooming equipment is usually tractors with very wide tracks that spread the snow around and compact it to make it dry and powdery. Regular grooming is an important part of the snowmaking process in ski resorts.
Snowmaking conditions have to be present in order for the snow making process to be a success. The right kind of ground weather has to be present for manmade snow to make it to the earth and stick just as with natural snow. Snow-makers are experienced snow machine operators who determine when the conditions are favorable for making snow.
Wet-bulb temperature is the most important factor for determining when conditions are favorable. Humidity is a very important factor in determining snow conditions. If the humidity is low enough, it can snow even with the temperature several degrees above freezing. If the humidity is too high, rain may be made instead of snow, because the air saturation slows the cooling process down to much.
Good snowmaking conditions are when the temperature is close to 30F and there is a relative humidity of less than 30 percent. If the temperature is less than 20F, making snow is easy even with higher humidity. Actually, the temperature in the teens is ideal for snowmaking. All the conditions have to be right for any snow to be man-made.