The Science of Snowmaking

Posted by Spence on 6th Nov 2019

The Science of Snowmaking

The Science of Snowmaking

When Mother Nature doesn’t cooperate, Holiday Valley’s snowmakers — assisted by a world-class automated snowmaking system — answer the call

*This post was originally published in the January '19 edition of Ellicottville Snowed-In*

Inside a nondescript garage adjacent to the Training Center at Holiday Valley, air compressors hum, radios cackle and TV monitors show happy skiers and snowboarders loading and unloading onto chairlifts. Jeff Clancy, leaning back in a computer chair, keeps a watchful eye on the 60” monitor showing a satellite image of the resort.

“Everything can be controlled from this room,” he explains, eyes scanning across the hundreds of dots that line the ski runs on the image. “And if we wanted, the entire system could run itself.”

                            Snowmaking at Holiday Valley

Clancy, Holiday Valley’s snowmaking supervisor, is referencing the HKD Automated Snowmaking System. We’re in the control room with snowmaker Kurt Rowland, and this is where the magic happens. Guns are turned on or off, on-hill weather centers measure humidity and wind direction, and problems can be dealt with swiftly as soon as they arise. From front to back, it’s an incredible marriage of technology, information and blue collar, hands-getting-dirty work.

Have you ever wondered how snow is made? It’s a far cry from flipping a switch when temperatures dip below 32º. In fact, that couldn’t be further from what happens. At its core, snowmaking is an art, and a science. When the weather gives us cold temperatures but no natural snow, it’s the snowmakers that save our hide.

“Three and a half acre-feet of snow an hour is our output at maximum capacity,” Clancy says. “We have two reservoirs of water - one across Route 219 (by the golf course) and Spruce Lake - that we pull from, which gives us the luxury of rarely running out. There are three pump houses, with the two main ones near The Wall. Water used for snowmaking runs through lines over the headwall or along Catwalk to access the rest of the resort.”

When “patch” snowmaking needs to happen (dedicating a number of guns to patch up thin spots on certain runs), the water pulls from across the street. But for the aptly-named Blitz - when temperatures plummet in late November and early December and it’s all systems go to get the resort open - the water comes from the 67-million-gallon Spruce.

“We add Snomax at the pump houses before the water distributes across the resort,” Clancy says. “Snomax is a snow inducer - it raises the freezing temperature of water, allowing us to make snow when the weather is warmer. The ratio of Snomax to water remains the same no matter how much water we’re pumping. The pump houses know to adjust accordingly.”

While snow can be made when it’s 28º all the way to -28º (both numbers represent degrees in Fahrenheit, eh!) the optimal temperature ranges between 10º and 15º. HKD’s guns allow for different types of snow to be made. When it’s in the high-20s, it’s very wet. When it’s sub-zero, it’s very fine. But when the temperatures hover in the mid-teens, it gives the snowmakers some leeway.

“If you’re running at maximum capacity when it’s -20º, the risks increase significantly,” Clancy said, referencing things such as guns breaking or electrical outages. “But we have no issues running guns when it’s 12º and having you (Clancy points at me) snowboard through them, because at that point, it’s a very fine powder that’s nice to rip on.”

Remember in school when they told you no two snowflakes are the same? For the white gold that falls from the sky, that rings true. Not in snowmaking. Snowflakes from guns are all the same — and that’s by design. Creating a consistent surface for skiers and snowboarders is of the utmost importance.

When the system maxes out at Holiday Valley, over 230 guns blaze. And of the 550 total guns the resort has on-hill, 331 run on the automated system. A recent NYSERDA grant allowed HV to purchase an additional 107 Impulse Tower guns, which will run manually this season before being absorbed into the overall automated system. The Massachusetts-based HKD, founded in 1971 by Herman Dupré, supplies the majority of the resort’s snowmaking guns, including hydrants, hoses and the PC-based HKD Tracker computer software. Over the past 46 years, the resort has reinvested over $13 million into its snowmaking capabilities.

“At the beginning of the season, if we’ve got optimal temperatures, we can have the entire system maxed out and running in about an hour,” Clancy said. “If we had to, we could do it in about half that time. But when you start flipping switches all at once and water starts pumping every which way, you’re jeopardizing it. If a line breaks, it can really mess up our day. So we ease into it. Before automation, it might take us 3-4 hours to get the entire system up.”

From his seat, Clancy begins navigating through the HKD software. On the giant screen, you see the gray dots — each representing a gun — and the 8 on-hill weather centers with real time information. Recently, the software upgraded to not only include all of the automated guns, but every gun at the resort. The guns connected to the automated system can be turned on and off from this seat. The guns not connected can’t be turned on, but they can be monitored.

“Let’s take Bear Cub,” Clancy says, referencing one run not yet on the automated system. “I can monitor all of the information, and when someone out there turns them on, I just mark them as “on” here on the computer. That allows us to gather a substantial amount of information we otherwise wouldn’t have been able to.”

Information and communication are critical aspects. Clancy needs to be able to see what’s running, what’s not and where his best windows are. For instance, each weather center gives dry bulb and wet bulb. Dry bulb is the actual temperature, while wet bulb is the relative temperature with humidity. Wet bulb gives the snowmakers a much more accurate temperature reading, as humidity plays a major role in snowmaking and the quality of the snow made.

“Some European resorts go full automation, meaning they set the parameters at the beginning of the season and just let it ride,” Clancy said. “We don’t do that here, because we want to have full control over what’s happening. There are too many variables and too many things that could go wrong to have the computer do it all season long by itself.”

A majority of the guns at Holiday Valley are HKD’s Impulse, which stand 30 feet tall weigh 120 pounds. The Impulse runs at 120 CFM (cubic feet of air per minute) in its first two selections, then 30 CFM its next two selections. These are different from the SV10 guns on Yodeler and School Haus, where each selection is 120 CFM. Layman’s terms: the 1st selection is less water, the 4th is most. The SV10 can make more snow faster because of the permanently higher CFM output (it’s stuck on high air).

“Most of the bonding - the actual making of the snow - happens externally,” Clancy said. “It’s called external nucleation. The high pressure water comes out of the nozzle and the air interrupts it, and the water molecules smash together. The newer guns, like the Impulse, do a lot of the work internally. Each year, the guns get more and more efficient.”

When you begin to think about it, the snowmaking capabilities at HV truly are astounding. From the man-made Spruce Lake to the installation of the guns to the know-how of working the software, it takes a crew as tight as Clancy’s to run it safely and efficiently. Even with the East Coast’s largest automated snowmaking system and the most energy efficient one in the country, at the end of the day it’s the product that matters the most.

“We love what we do, because we love when we see people out there enjoying it,” Clancy said. “We take a lot of pride in our work. Without knowing what the season is going to bring in terms of natural snowfall, we’re always prepared.”

If you see a snowmaker out and about, be sure to buy them a beer. And celebrate with them at Lords of Snow, the snowmaker’s appreciation party held each spring at Villaggio. More information on Holiday Valley’s snowmaking system can be found at