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How Ski Roundtop Makes Snow |
Each winter, an amazing transformation takes place at Ski Roundtop. 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 no, it's true! here's why:
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This is a natural snow flake. The classic flake has the six arms on it like this one. Pretty? You bet. Fluffy? For a while... |
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This is a drawing of a machine made snow crystal. No arms, just a nice round ball of snow. |
As we groom and ski/ride on the snow, all snow crystals get compressed. If the temperatures go above 32 degrees, they begin to melt. Let's see how that affects the shape of the crystals:
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The arms break off very quickly and because of the much greater surface area, the crystal melts much faster. The properties of the crystal have changed dramatically.
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The machine made crystal has shrunk a bit, but it still has the same basic structure. With less surface area, less melting occurs. The properites of the crystal have not changed much overall
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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!
Below is a step by step tour of Ski Roundtop's snowmaking system. |
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Ski Roundtop 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. |
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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. |
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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. This year we added 19 new towers on the slopes allowing us to make more snow with less "air". |
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. |
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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. |
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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.
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Snow "Guns" come in two basic types Air/Water and Airless.
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.
This year we have installed a computerized airless system on Exhibition. 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. We'll post a story about that system soon. |
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Where Do We Get The Water? |
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Considering that snowmaking relies on a steady water supply, you may be concerned about where we get it. 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. |
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