Snowmaking header: Snowguns blowing on White Heat.


The most dependable snow in New England.

At Sunday River, snow is what we do best. We have the most powerful and technically advanced snowmaking system on the planet and a dedicated team of snowmakers who commit to producing the best conditions around—all season, every season. In the last ten years, we have spent $7 million in new guns alone, so that you can book your trip with confidence and enjoy your days on the mountain whenever you come. We've even created a Snow Guarantee.

Snowmaking, in principle, is relatively simple. Water is pulled from a source, pumped onto the mountain, and forced through a nozzle by pressurized air. From there, the water droplets freeze into snow crystals and settle to the ground. So, what separates Sunday River from everyone else? There are two pieces to that answer. First, we're able to maximize each step of the snowmaking process. And secondly, we're committed to making snow whenever Mother Nature lets up in her efforts. Not only are we able to make snow when some other resorts can't, we're willing to do so when others won't. Want to learn more? Welcome to Snowmaking 101.


It sounds impressive when a ski area can claim to cover over 90 percent of its terrain with snowmaking. But far more relevant to skiers and snowboarders is the amount of snow a ski area can make at one time; this is the only true measure of how fast an area can open new terrain or refresh trails during the season.

Since water is the raw material from which snow is made, water supply is a critical determinant in how much snow a ski area can make. Most ski areas are located near the top of a watershed and depend on relatively small water sources, or rely on ponds. Sunday River, on the other hand, is blessed to be located near the bottom of a huge watershed with nearly 43 square miles of drainage. Our water is pulled directly from the Sunday River and is constantly replenished. Our system can currently pump 8,100 gallons per minute from the river to the resort and then pump the same 8,100 per minute up onto the mountain. If we were to add additional pumping capacity, we are permitted to draw up to 50,000 gallons per minute from the river. Once the snow melts in the spring, it returns to the same watershed and river.


In addition to water, air also determines overall system capacity. Air is measured in volume and pressure. Sunday River operates the world's largest high-pressure snowmaking system and can compress about 54,000 cubic feet of air each minute. The high volume and pressurized system allows Sunday River to make more snow than any other resort and allows us to control the process to ensure consistent snow texture from the top to the bottom of each trail. This air capacity allows us to run over 300 low-energy guns simultaneously.

HKD Snowguns at Sunday River

On-Mountain Infrastructure

Obviously, air and water capacity are the two biggest factors in snowmaking, but there are two others: the number of guns in the snowmaker's arsenal, and the spacing of the hydrants on the mountain. Some ski areas own only enough guns to match their maximum water and air capacity, so after making snow on one trail crews must move all of the guns and hoses to the next trail. Sunday River's arsenal includes over 2,000 snow guns and 30 miles of hose --enough to leave guns set up all winter long on each trail. These are spread along 80 miles of snowmaking pipes that span all eight of our mountain peaks. Hydrant spacing is also a factor. Many resorts space hydrants up to 200 feet apart-meaning that each gun must cover a much larger area of the trail. Sunday River utilizes an average hydrant spacing of 85 feet and on trails intended for early season skiing and riding, hydrants are placed as few as 30 feet apart. Larger spaces between hydrants also tend to produce large "whales" of snow that must then be pushed around by groomers. This packs the new snow down and doesn't allow water a chance to seep out, resulting in hard, sometimes icy snow. By spreading snow evenly as it's made as opposed to afterward, Sunday River can generally avoid grooming new snow for at least 24 hours, allowing the snow to "cure" or dry.

On-Mountain System By the Numbers

  • Snowguns: Over 2,000
  • Miles of pipe: 80
  • Miles of hose: 30
  • Hydrant stations: 2,200

Skiing on fresh snowmaking


Sunday River's history with snowmaking goes back to the 1970s, when we were the first ski area in Maine to implement snow guns into mountain operations. The snowmakers found that the guns on the market were not producing enough snow to meet the demand, so in the early 80s, the SR 7 was invented in-house. Today, the SR 7 guns are on their way to retirement to make room for new technology, but the innovation and drive to make the most dependable snow in New England is still a large part of Sunday River's character.

Our snow gun arsenal is comprised of two different elements beyond the SR 7 heads. On South Ridge, you'll find 80 Boyne Low-E Fan Guns, developed by our parent company, Boyne Resorts. The Boyne Low-E gun converts water into snow crystals more efficiently, especially at marginal temperatures above 25 degrees. This greatly improves snow quality and reduces icy build-up while boosting energy and water efficiencies more than any previous technology. With the Boyne Low-E Fan Gun, compressed air is injected with a very small amount of water in an inner ring at the center of the gun. This compressed air/water mixture then freezes as it's propelled by the fan and merges with water from the outside nozzles to create crystals. The extended and tapered nose cone adds about 18 inches to the overall length and improves expansion cooling as the air leaves the gun. The greater the expansion cooling, the more water freezes. The unique shape and additional length raises velocity and distributes snow further, allowing more hang time for powdery snow. However, the true secret weapon in this snowgun is the exclusive Boyne-designed water bath technology that is capable of yielding higher production output while achieving lower energy consumption. The combination of each of these modifications has created a one-of-a-kind fan gun only found at Boyne resorts.

The guns that are most common and most effective around the resort come from HKD Snowmakers, most predominantly 850 Impulse heads which are mounted on towers. This positions the snowguns high above the trails to allow snow crystals more time to freeze in the air before settling down on trails, and allows each gun to cover a greater surface area. The heads themselves are designed to be energy efficient, enabling us to make more snow using less energy, and allowing us to run more snowguns at one time.  

The HKD Impulse heads are energy efficient because they are able to make snow using less air pressure. When temperatures are marginal for making snow, they use about 120 cubic feet of air per minute (CFM), but as temperatures get colder, the HKD Impulse head drops as low as 30CFM, which is drastically lower than most snowguns on the market. Valves on these snowguns help our snowmakers to adjust the quality of snow being produced, meaning that as the temperature drops, more water can be pushed through the head using less air pressure.

In our T72 and 3D terrain parks, we use the HKD Method snowgun heads. These heads pump up to 110 gallons of water per minute with a consistent air pressure of 120 CFM, making more snow at a faster rate-meaning our terrain park jump lines can be built even quicker.

Sunday River was also the first to utilize computers to actually control snow quality. Some ski areas rely on snowmaking crews to literally hold their coat sleeves in a plume of snow to judge its quality. At Sunday River, a snowmaker calls the pump house by radio and gives his or her location. The crew chief then enters this location into the computer, which calculates the optimum setting for the guns there, based on the air, water pressure, and weather data, including temperature and humidity, which is relayed by remote weather stations at different elevation bands on the mountain. On each run, the crews check the settings and move the guns to ensure that coverage and snow quality is not only optimal, but consistent.

The Future

Snowmaking is a big part of Sunday River's history and will always be part of our future. As we look toward the future, we will continue investing in our snowmaking system and making each part of the snowmaking chain more efficient and more powerful. This means more snowguns, new technologies, and some big steps forward, like our plan to double the water capacity of our system.

Life of a Snowmaker

Have you ever wondered what it's like to be a Sunday River snowmaker? Our snowmaking crew is constantly hard at work, whether they are prepping for the next cold spell or hiking the trails in the middle of the night adjusting the guns. To see snowmaking from the inside, we've created a photo blog, Life of a Snowmaker, featuring submissions from our team to show the conditions they work in, their favorite parts of the job, and most importantly, all of that beautiful Sunday River snow.  

At the heart of snowmaking at Sunday River, however, is our snowmaking team. Snowmaking is a tough job anywhere, but the team at Sunday River has proven year after year that they have the tenacity, passion and expertise to be the best and most accomplished snowmakers in the world. In 2016 our team was recognized by Ski Area Management magazine and HKD Snowmakers as winners of their I Am A Snowmaker contest, which included resorts from across North America.  Below you'll find their video from this contest, as well as an earlier video about the team and what it takes to be a snowmaker at Sunday River.

I Am A Snowmaker Contest

Man Vs. Weather