The atmospheric factors affecting snowmaking are (in order of importance):

	TEMPERATURE
	RELATIVE HUMIDITY
	WIND SPEED
	WIND DIRECTION (Relative to Gun)
	ALTITUDE
	SOLAR RADIATION

Temperature, relative humidity, and altitude can be combined into a single factor called the "wet-bulb temperature". This is the temperature a wet thermometer will be cooled to if air is blown over it - a condition similar to what the water droplets are being exposed to during snowmaking. When the air temperature is close to freezing, the wet-bulb temperature becomes important. In fact with the right equipment, snowmaking can take place at 40 degrees Fahrenheit if the relative humidity is low enough to yield a wt-bulb temperature below 32 degrees Fahrenheit. This may seem a bit bizarre but the weather in the western U.S. frequently allows this. The key to efficiency is the ration of air to water at a given wet-bulb temperature. 

Don't try to fight the wind - you'll lose. Aim the gun with the wind. You'll be able to add more water to the gun and make increased volumes of dryer snow. If necessary, add an extra length of hose to get the snow where you want it. Start making snow with the hose fully extended, periodically pulling the gun backwards in a zig-zag fashion, during the night/day until you are finished. This will cause the snow to be layered and evenly distributed. If you do make wet snow, it will be covered with dry snow each time you pull the gun back, leaving a perfect surface when you're done.

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Place the gun in the center of the trail if there is no wind or if the wind is blowing in line with the trail, and aim the fun up or down the trail with whatever wind there is. This sill allow you to build broad, smooth mounds of snow in the center of the trail where it belongs. The skiers will spread the snow out to the edges for you. 

Get to know the wind characteristics of your mountain! Does it tend to change as the sun sets? If you can predict where the wind will go, you will save yourself a lot of work.

Aim the gun up at about a 35 degree angle. This will allow you to put more water to the gun and more than compensates for any extra loss of snow off-trail. It often appears that more snow is lost off-trail than really is. During atomization of the water, as each main droplet is formed there are also two very small droplets formed due to a harmonic when the main droplet breaks off. These tiny droplets tend to be very reflective and noticeable although they contain only a very small portion of the total snow produced. Frequently they are carried upwards by convection and disappear altogether. Fortunately they are not significant, the vast majority of the snow is falling relatively near the gun.

Try to let the snow set up before grooming. Man-made snow is dense enough, it doesn't need to be compacted. The first day is the most important. Ice is continually sublimating (evaporating) and recrystalizing into a bonded mass. Grooming will compress the snow squeezing out air pockets if the snow is not allowed to set up first. This is where layering the snow with a dry layer on top can help reduce the need for grooming.

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When trying to cover ice, always start by making wet snow then cover it with dryer snow. this bonds the snow to the ice and builds a durable base that won't be worn off as quickly. You should also make damp snow when the wind is blowing hard enough to drift dry snow. 

Small output snowguns tend to be more efficient than large output snowguns of similar design. This is most obvious in warm weather when the water to a large gun has to be throttled way back due to the limited cooling effect of the air within its plume.

Large systems should be designed to run a gun on every hydrant of a given trail simultaneously. This allows you to cover a complete trail overnight efficiently, without continuously moving guns. This also makes smaller guns more practical.

Tower-mounted guns can be more efficient than guns on the ground, allowing more time for the droplets to freeze, therefore more water can be put to the gun and a better ratio of air to water can be obtained. Placement is very important with towers and most ski areas still need some guns on the ground for specific locations and wind conditions. 

Have an extra set of guns. Frequently this improves system efficiency by 25% if a ski area desires to change trails frequently. The second set of guns can be setup in advance during a shift change, greatly reducing downtime when you change trails.

A good air-to-air aftercooler/demister is worth is weight in gold. The dew point of the compressed air should be reduced to within a few degrees of the outside air temperature to minimize rime ice in the air hose. Changing hoses is not fun and very inefficient in the long run. Choose an aftercooler with at least twice the capacity you think you need.

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