How We Make Snow
Each winter, an amazing transformation takes place at Roundtop Mountain Resort. Even though Mother Nature does not provide much snow in this region, the slopes are always covered with fresh snow. How do we do it? We're glad you asked!
Machine made snow is made up of exactly the same stuff as natural snow - frozen water. When the weather provides cold temperatures, but no moisture, our snowmaking team simply adds just the right amount of moisture to the atmosphere to produce excellent snow. It may sound easy, but making great snow requires millions of dollars in specialized equipment and an experienced team of snowmakers.
You may have heard people say that machine made snow is more durable than natural snow. Believe it or not, it's true! here's why:
The classic six sided natural snowflake is soft and fluffy when it falls from the sky. That's why natural snow can be so fluffy at first - it is mostly air. However, over time the little branches break off and because of the greater surface area the crystal melts faster too. The properties of the snow change dramatically.
Machine made snow looks more like little round balls. As time goes by, the machine made crystal may shrink, but the basic shape stays the same longer. Since it is a ball, it has a smaller surface area so it melts slower too. Therefore, you can groom and ski on machine made snow and it will retain it's original properties longer.
We Work With the Weather
Now a little bit about the weather. Just like Mother Nature, we need temperatures of 32 degrees or lower to make snow. But 32 doesn't always equal 32! Snowmakers work from the "Wet Bulb" temperature. The wet bulb takes the amount of humidity in the air and evaporative cooling into account. The wet bulb temperature is usually colder than dry bulb (the kind most people use) so it may appear that we can make snow above 32 degrees at times. The rule of thumb is that as the temperature and humidity go down, the amount of snow we make goes up!
It All Begins As Water
Roundtop Mountain Resort has snowmaking ponds with a total capacity of over 35 million gallons! All of the machine made snow you see on the slopes started out in our snowmaking ponds...and will eventually return there after the ski season ends.
In order to make snow, we need to pump cold water up the hill - 4,000 gallons per minute when running at full capacity. Our 5 vertical turbine water pumps take water from the ponds and pump it up the mountain. You may notice the fountain in the snowmaking pond near the maintenance area. That's not just for looks, it helps cool the water, which makes snowmaking work better.
Air is the Other Half of the Equation
But water is only half of the story. Most snow making equipment also requires compressed air - a lot of it! Our 10 compressors produce up to 30,750 cfm of air at full capacity. Producing compressed air is the most expensive part of snowmaking. Newer tower mounted "fan" guns use much less compressed air so they are more efficient. Each season we add more high efficiency "airless" snowmaking equipment, allowing us to make more snow with less energy. In fact, even at full capacity we seldom run more than two compressors these days.
Unfortunately, compressed air comes out of the compressor very hot (180 degrees), obviously not good for snowmaking. Before the air goes up the hill, it is run through huge air coolers to bring the temperature down to a more reasonable 36 degrees. Even the "airless" fan guns require a little compressed air to operate.
Then You Have to Mix It Just Right
So now we have a lot of cold water and a lot of cold air - what's next? There are two sets of pipes running under every slope - over 9 miles of pipe in all. One set distributes air, one set distributes water to over 350 snowmaking hydrant pairs.
When we are ready to make snow, we connect "snow guns" to the snowmaking stations. The "guns" allow our snowmaking crew to mix just the right amount of air and water to produce snow on the slopes.
Air/Water guns rely on compressed air to propel the water through the gun and into the air to make snow. Obviously they use a lot of compressed air to accomplish this. However, since we can adjust both the amount of water and the amount of compressed air very precisely, this system tends to work well in marginal temperatures.
Airless (or fan) guns use a large fan to propel the water into the air to make snow. They only require a very small amount of compressed air to keep things moving. On the front of the gun there is a series of rings with water nozzles on them. As the temperature goes up or down, we can open or close rings to adjust the amount of water we are using.
Most of our airless guns are mounted on towers. The reason is that if we spray the water high into the air, it has more time to fall before it hits the slope. That gives it more time to freeze and dry out. Since we can use more water, we can make more snow. In addition colder/dryer snow is a better surface for skiing and snowboarding too.
Many of our airless tower guns are now automated. This means that we can turn them on and off by computer rather than having to hike to them and do it manually. The towers are equipped with their own weather station and they can "talk" to each other. As the temperatures go up or down, the system adjusts the amount of water being used automatically to make the best snow possible.
Doesn't That Waste Water?
First, it is important to note that snowmaking doesn't consume water, it only stores it as snow on our slopes. The water used for snowmaking is surface water that we have stored in our snowmaking ponds. The ponds fill up naturally from rainfall and snow melt. At the end of the season, the snow melts and the water returns to the ponds.