How Do Ski Resorts Make Snow?

If you’re thinking about taking a vacation at a ski resort, it’s important that there be plenty of snow on the slopes. But it begs the question, how do ski resorts make snow?

Ski resorts make snow by blowing water droplets into the air with a device called a snow gun. The temperature should be at or below freezing and the humidity low. The snow gun forces tiny droplets of water high into the sky giving it time to freeze. The droplets fall as snow.

What’s Needed to Make Snow?

There are seven things that need to come together in order for a ski resort to make snow.

  1. Access to water
  2. Pumping capacity
  3. Cold temperatures
  4. Low humidity
  5. The need to make snow
  6. Automation
  7. A lot of money

Access to Water

As you can imagine, it takes a LOT of water to make all that powder at a ski resort. The resort must be near lakes or rivers in order to make snow. In fact, it’s such a huge undertaking that resorts work year-round to maintain the infrastructure to pump all that water uphill.

How much water do they need?

Resorts are pulling anywhere from 10,000 to 12,000 gallons of water uphill per minute!

That means there needs to be a water source that can accommodate that amount of water.

Resorts closer to the ocean tend to have access to virtually unlimited water supplies. I say “virtually unlimited” because there aren’t usually any restrictions to how much water can be pumped because there’s so much of it.

These tend to be resorts in the New England, New York, and Pennsylvania areas.

Western resorts are a different story.

Western resorts have to deal with water rights and minimum stream flows. States that have to deal with water rights are Colorado, Idaho, Oregon, New Mexico, Utah, Wyoming, Montana, and Nevada. As you can see from the list, states that have to abide by water rights laws contain federally reserved public lands, such as national forests, national recreation areas, and national wildlife refuges.

Pumping Capacity

Once there is a good source of water, the next challenge is getting that water to the top of the mountain so resorts can start making snow. This is called “pumping capacity”.

Pumping capacity refers to how much water can be pumped from the water source to the snow guns. This is measured in gallons per minute uphill. Killington Ski Resort is the leader, being able to pump 12,000 gallons per minute uphill.

Not to be outdone on the West Coast is Beaver Creek, Colorado. They can move 10,000 gallons of water per minute.

Resorts work year-round to make sure the equipment needed to move all that water uphill stays in good working order. This is despite the fact that the ski business is only open 100 days per year.

Cold Temperatures

This one seems obvious. After all, it doesn’t snow in the summertime. So it makes sense that cold temperatures are needed to make snow.

But you might be surprised to learn that it’s not that simple.

Yes, freezing temperatures are an absolute necessity to make snow. The ideal temperature range for making snow is between -5 degrees to -20 degrees Celsius. That converts to about 23 degrees to -4 degrees Fahrenheit. There’s a reason this temperature range is ideal.

We’ll talk about that in the next point.

Having the right temperate range isn’t the only thing needed to make snow. It has to be this cold for a sustained period. When the temperature is in the ideal range, making snow becomes a 24/7 operation with day and night shifts. The longest run for snowmaking is around 4 – 6 days.

Humidity

snowboarder with snow plume behind him

When we think of humidity, the way we feel in the summer with sweat dripping off while sitting in the shade comes to mind. So we associate humidity with moisture or “wetness” in the air.

Would you be surprised to know that humidity exists in snow making season? And it plays a very important role in the production of snow.

We’ll talk more about snow guns later, but snow guns are what shoot the water into the sky to create snow. If the humidity is low, the water drops freeze more quickly due to evaporation.

This is the same effect that water has on you when you get out of the shower with drops of water on your skin. When you leave the wet environment of the shower and enter a dryer room, you get the shivers. This phenomenon is known as “evaporational cooling”.

The same thing is happening to the water droplets to make snow. If the temperature is right and the humidity is low, blowing water droplets into the air will produce snow.

As you might expect, there is a formula for determining the ideal time to make snow. It’s called “wet-bulb temperature”. Wet-bulb temperature is calculated like this:

Actual air temperature + humidity = wet-bulb temperature

Here’s an example:

If the air temperature is 32 degrees Fahrenheit and the humidity is 25%, the wet-bulb temperate is 22 degrees. That’s a good wet-bulb temperature. As we stated earlier, if it gets colder and assuming the humidity at 25%, it creates an even better wet-bulb temperature.

Having the right wet-bulb temperature is critical to making snow.

The Need to Make Snow

Because the ski resort season only last 100 days, it’s important to be able to make snow for it to last the entire season. If resorts relied only on natural snow, some resorts wouldn’t be able to run their base areas. Others wouldn’t be able to open at all.

To fill this need, ski resorts start laying down snow early. Because the key to good skiing is a very large quantity of snow. And the only way to do that is for resorts to do this is to produce it themselves.

Another reason resorts make snow is because the ski season will have multiple thaws and refreezes. In order to keep enough snow on the slopes, resorts have to produce their own snow.

Automation

Now that we know that we need the ideal temperature range combined with low humidity to make snow, and that this combination needs to be extended for at least 4 days, how do resorts make the most use of snow making equipment?

They automate it. More specifically, it’s computerized.

The computers keep track of weather and weather conditions automatically. The system then uses this information to combine the exact air and water mixture to create the best quality of snow.

Some resorts don’t use automation. This means those maintaining the property have to keep track of the weather and turn the snow guns on and off manually. Using an automated system can save up to 30% in labor costs.

This cost savings comes because the computers can automatically start and stop snow production at the exact moment when conditions are ideal.

A Lot of Money

As you can imagine, installing and maintaining automated equipment that pulls 10,000 to 12,000 gallons of water a minute uphill is going to cost a lot of money. The biggest costs are labor and electricity.

The labor costs are understandable. But electricity?

That’s because the pumps that pull the water uphill need lots of power. And even though modern snow guns are very efficient (some using only 5 watts of electricity), you need a number of them.

Consider this: To cover an acre with 12 inches of snow costs between $1,000 and $2,000. It can take between 1 to 6 hours to cover that acre. Most ski resorts make snow for 1,000 and 2,000 hours per season. That means that the total cost of making snow for a season can be upwards of $2,000,000.

For perspective, Heavenly Ski Resort in Lake Tahoe has 4,800 skiable acres. We don’t know what the cost is exactly to run the resort. But if we use their numbers combined with the $1,000 to $2,000/acre formula, it would cost Heavenly between $4,800,000 and $9,600,000/per season to create snow.

Wow. Almost 10 million dollars to put snow on the ground.

But that begs the question, since it costs so much money to create snow, is natural snow better for skiing than man-made snow?

Is Natural Snow Better for Skiing Than Man-made Snow?

After a fresh snowfall, natural snow is good for skiing. However, natural snow compresses. A lot. Uncompacted snow is mostly 90% to 95% trapped air. In fact, 1 foot of natural snow will compress to 1 inch.

This is why fresh snow is better for skiing than the days afterward. Man-made snow allows for this same type of experience even when there is no snowfall.

Man-made snow has other benefits over natural snow.

One thing that makes man-made snow better than natural snow is that it lasts a lot longer. It’s produced in a way that allows water to leak through it. So if it rains, the snow has a better chance of surviving the rainfall than natural snow.

Man-made snow is also denser. Because it’s denser, it can withstand warm weather longer than natural snow. That’s important for ski resorts. Some resorts have areas that are 10ft plus as late as the month of May.

This man-made snow is sometimes called “white asphalt”. That’s because it can be laid down in such a way that it is very durable and the water will leak through it. And since the key to good skiing is having a lot of snow early in the winter, putting down a very large base of man-made snow is important.

Different Types of Snow Guns

The process of producing snow requires the use of snow guns. There are two types of snow guns:

  • Carriage
  • Pole mounted

Both of these type of snow guns is important to produce snow at a ski resort.

Carriage Snow Gun

Snowfall is not always an even process. Some areas may receive more snow than others. If that happens at a ski resort, a backup plan has to go into effect.

Enter carriage snow guns. These snow guns can be picked up with a groomer and taken where the snow is needed. This allows the resort to put more snow on areas that need it wherever that may be.

Pole Mounted Fan Gun

This is what most people are used to seeing at ski resorts. The gun is mounted high up on a pole, thus the name. Because it’s fixed, the snow it produces is confined to the area in the vicinity of the gun.

Unlike the carriage snow gun, pole mounted snow guns ensure that high traffic parts of the resort have enough snow in the right amount.

How Do Snow Guns Work?

The largest producer of snow guns in North America is a company called SMI out of Michigan. Some SMI units can produce water pressure as high as 500psi (pounds per square inch).

We’ve stated that there are two types of snow guns: carriage and pole mounted. I’m here to tell you that the distinctions go even further. This involves how the water is ejected from the snow gun. There are two types.

The first uses compressed air and water. These units take water from the attached hose and uses compressed air to split the water stream into tiny droplets. These fly high into the sky giving them time to freeze. When it falls to the ground, you have snow.

This is a cheaper option to produce snow and requires 2 inputs: water and compress air.

The second type requires only one input: water.

Instead of using compressed air, it uses an electric fan to blow the stream of water into the air. This is called an airless snow gun. It doesn’t need a hose for compressed air. But it does require an electrical connection to run the fan.

Fake Snow Vs. Man-made Snow

I’ve used a few terms in the article that might cause confusion. I’ve repeatedly used the expression “man-made snow”. Some might use the term “fake snow” interchangeably with “man-made snow”.

There is a very big difference.

Man-made Snow

Man-made snow is made by forcing water high into the sky as droplets. When these droplets fall to the ground, it produces snow. Since the only thing involved in producing man-made snow is water and air, this snow is completely safe.

If you picked up a handful of man-made snow and put it in your mouth, it would be no different than natural snow. No artificial products or chemicals are used to produce the snow.

The only difference between man-made snow and natural snow is that one falls from clouds in the sky and the other is blown into the sky from the ground.

Fake Snow

“Fake snow” is something altogether different from man-made snow. Fake snow is what you typically see being sold to make your home look like it has snowed.

There are 2 types of fake snow: powders that are mixed with water and spray-on aerosols.

“Instant snow” is a powder that tuns into artificial snowflakes when mixed with water. The compound is made of a non-toxic polymer.

The second type is an aerosol. You may see this type of fake snow sold as:

  • Snow spray
  • Flocking snow
  • Holiday snow

These products leave a snow-like residue behind that is made up mostly of fat or calcium after they are sprayed.

Neither of these products is likely to cause poisoning. However, if they get sprayed into the eyes or on the skin, there might be mild pain or redness. To minimize irritation, gently rinse the eyes with water at a comfortable temperature.

If you think these or any products are causing problems, in the United States you can call poison control at 800-222-1222 or go to the webPOISONControl website.

Not for Skiing or Winter Sports

Even though it’s probably obvious, I have to expressly make it clear: “fake snow” is not good for skiing or winter sports. The only thing it’s good for is decorating the house to make it “look” like snow fell. It doesn’t have the consistency or texture to real or man-made snow because it “isn’t” snow.

Time to Hit the Slopes

Now that you know how resorts make snow, it’s time to book yourself a vacation to a ski resort. You can use the form below to find the best ski resort for you.

If you don’t know the names of any ski resorts, try typing “ski resort” along with the name of the state or the area you’re thinking about. Here are some ideas:

  • Ski resort Colorado
  • Ski resort Vermont
  • Ski resort Lake Tahoe
  • Ski resort Poconos

Try whatever combination works for you. And if you found this information useful, please share it with your friends and on social media.

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