I can answer any of you snowmaking questions since I happen to be a snowmaking foreman for a ski area...
First, here are some links to snow machine companies:
www.snowmakers.com
www.yorksnow.com
www.ratnik.com
www.snowgun.com
www.lenkosnow.com
Here's the crash course in snowmaking. I've had this saved on my computer for years, it's the best write up on snowmaking I've ever found. This came from SMI's website years ago. They now have an abbreviated version of it on their site but this version gives a much more in depth explanation of snowmaking.
The article describes it as well as I could (and I don't have to type it all out since I can just copy and paste it
).
WHAT IS SNOWMAKING?
(Snow - crystallized ice particles having physical integrity and the strength to maintain their shape).
When nature doesn't cooperate by providing natural snow, snowmakers take over. Given water, electric or diesel energy and temperatures below 32 deg;F (0 deg;C) snowmakers can provide snow. Basically snow is small particles of ice. So, the really old way of making snow and the way they still do in the tropics is to grind up blocks of ice. But this is very expensive. So, if possible, machines that convert water into snow directly and on site are used. These snowmaking machines make snow by breaking water into small particles, cooling the water by causing them to move through cold air, nucleating the water particles and distributing the resulting snow on a surface. Why don't people just sprinkle water to make snow? Water is a unique material, it expands when it freezes and it has high heat of fusion, thus your ice cubes float and last a long time. Heat of fusion means that one can cool a pound of water say from 65 deg;F (18.3 deg;C) to 64 deg;F (17.8 deg;C) or 34 deg;F (1.1 deg;C) to 33 deg;F (.6 deg;C) by removing 1 BTU. But to convert one pound of liquid water at 32 deg;F (0 deg;C) from a liquid to one pound of ice at 32 deg;F (0 deg;C) requires the removal of 144 BTUs. Thus, a large amount of heat removal (cooling) is required. Also, water can be cooled well below 32 deg;F (0 deg;C) and still stay a liquid unless it is nucleated. So a snowmaking machine a) breaks the water into small particles, b) cools the water to 32 deg;F (0 deg;C), c) removes the heat of fusion and d) nucleates.
Most requirements for snow require relatively large quantities of water, for example to cover an area of 200 feet (61 meters) by 200 feet (61 meters) with 6 inches (15 centimeters) of snow, one would need 20,000 cubic feet (566 cubic meters) of snow or 10,000 cubic feet (283 cubic meters) of water. This is 75,000 gallons (285,000 liters) of water or ten truck tankers full. Thus, an excellent water supply is needed and the water pressure should be at least 100 PSI (pounds per square inch) (7 Bar) or 230 feet TDH (total dynamic head). Many ski areas can convert over 2,000 gallons (7600 liters) per minute of water into snow. This is eight tons per minute or 500 tons per hour. Or stated another way, a truckload every three minutes or less.
Snowmaking, while usually used at ski areas, is also used for frost protection on construction projects, freeze protection of crops, automotive and aircraft testing and sewage disposal. There are over thirty snowmaking companies around the world.
Humidity and Snowmaking
The lower the humidity, the more snow a system can make at a given temperature. Any system! This is because evaporation furnishes a significant part of the cooling in the snowmaking process. So, the lower the humidity, the more evaporation per unit of water, the more snow you can make. Going from 85% humidity to 40% humidity can sometimes double the amount of snow made even at the same temperature. Thus, it is recommended to use Wet Bulb temperature to determine snow production. The Wet Bulb temperature is the lowest temperature a water droplet can reach in the atmosphere and takes into account both temperature and relative humidity.
Marginal Temperature and Snowmaking
Most snowmaking systems can make snow above 25 deg;F
(-4 deg;C) Wet Bulb but above 28 deg;F (-2 deg;C) Wet Bulb they will do little more than dust the area. Compressed air systems have seen conditions where snow was made as high as 40 deg;F (4 deg;C) for up to an hour, but the humidities must be extremely low. But to get "commercial" quantities without excessive energy consumption, temperatures below 28 deg;F (-2 deg;C) Wet Bulb are usually required. If you do have consistent temperatures above 25 deg;F (-4 deg;C), a larger snowmaking system may be necessary. Also, putting the snowmaking in the air will maximize the system's effectiveness (tower or boom mounts). This increases the residence time of the water particles in the cold air and more snow can be made. The best man-made snow is of spherical structure as to give a feeling of skiing on ball bearings, allowing edges to hold and turns to be carved.
Rain and Snowmaking
The distinctive ball bearing characteristic of better man-made snow allows rain to drain through it without destroying the snow structure. Thus, more snow remains with minimum surface ice. Natural snow on the other hand with its fine crystal structure tends to accumulate water from rain at the surface of the snow. Also, the rain tends to cause natural snow crystals to break down and to dissolve with subsequent ice formation.
Snowmaking and Snow Quality
Why Should I Make Snow? To get open, to stay open, to provide a base, to give the best skiing conditions possible, and for cosmetics. In all these cases you are looking for volume, doing the job as quickly as possible, and doing it at a minimum cost. In none of these instances does it make sense (cents) to make dry snow. If a snowmaker can make 2-3 times as much snow using the same amount of time and cost (and this is the case for wet snow compared to dry snow), profitable management requires that wet snow be made. Of course, we are talking about quality snow that meets the test described below.
What Is the Best Quality Snow?
According to most successful ski area operators, the best base snow is large particle wet snow--not so wet as to discolor or bleed, but much wetter than fresh natural snow. The best surface snow may be a dry snow. Why? Natural snow will become more dense with age. So, most experienced snowmakers make snow that is like three-day-old natural snow. It lasts longer, holds up better, resists blowing away, grooms easier, and is the most energy efficient to make. Wetter snow is more efficient because more snow can be made with the same amount of equipment, the same amount of horsepower and the same number of people.
How Do You Determine Snow Quality?
To check snow quality during snowmaking:
1) Squeeze a handful--if a few drops of water come out, it is OK; no drops of water, too dry; substantial water, too wet.
2) Kick the snow with your toe--if it comes out ball bearing size, OK; flies up as dust, too dry; golf ball size or larger, too wet.
3) Let the snow fall on your arm--if it hits and bounces, OK; flutters down as dust, too dry; goes splat, too wet.
These tests show snow wetter than natural snow, but good machine-made snow. Always plan on grooming machine-made snow. It will last longer and ski better. But it is best to let snow piles cure at least 24 hours before touching the pile.
So that's that... If there are any more questions, lemme know!