Snowmaking in the Time of Drought Sustainable Play

THAT THE SIERRA might not be so very nevada one day might have been inconceivable to the Spaniards who named the range, or to members of the Donner Party who struggled through house-high drifts, or to those World War II-era entrepreneurs who built ski lifts reaching to the tops of Mammoth Mountain, Tahoe’s Slide Mountain, Mount Lincoln, Heavenly Peak, and Squaw Peak. But Sierran snow seems to have become more fickle. Although there have been the hallelujah winters that buried slopes come Halloween and didn’t desist until Memorial Day, California’s climatologists have long predicted that Sierra winters will wane, with rain invading the snowpack, and with snow falling on only on the highest of slopes. This is proving to be plainly true. Snow data rolling in from California’s monthly measurements indicate depths of just 14 percent of the snowpack. Snow area operators have been firing their snow cannons since late October.

Pondering these data and appraising the dry slopes around my home in the Carson Range seems like déjà vu all over again. In January 2013, the second year of the recent five-year drought that desiccated the Sierra, I drove up the Mt. Rose Highway and beheld bare earth everywhere, even at the 9,000-foot summit. And as I traversed the dun flats towards Truckee, I glanced in my rear-view mirror and was gobsmacked by a sight so utterly bizarre that I nearly lost control of my car: a mountain seemingly coated in confectioners’ sugar amidst an otherwise drought-choked landscape. This was Northstar-at-Tahoe, of course, Vail’s North Shore ski hill.

I’ve seen many an artificial snowpack in my 35 years of skiing – southern Michigan’s Mt. Holly comes to mind, where I made my first tentative turns — but I had never seen an entire mountain of such scale dressed in winter whites from base to summit. I’ve seldom thought of ski hills as amusement park rides, but looking at Northstar, I flashed on my first sight of Disneyland’s Matterhorn looming aside California’s Interstate-5.

Most of all, I wondered about the vast quantities of natural resources that went into the making of the mountain (which by this time I had pulled to the side of the road to more fully and safely take in). Within several weeks USA Today would report that Boreal Ski Resort, the small operation that sits astride Donner Summit, had already consumed a record-setting 32 million gallons of water to open five of its 41 trails to the public.

Ski area operators have been busily funneling more of their water rights into the manufacture of snow until the day they will be forced to line their slopes with some water-free simulacrum. What amount of water is lost in the snowmaking process, and to what extent, if any, is air is befouled by the CO2 produced as a byproduct — not just on a resort-by-resort basis, but region-wide — like throughout the Tahoe Basin?

And based on the paucity of data, how come nobody seems to care?


“What you want to do is take the water and break it into as small a droplet as possible. Then you want to have those droplets falling down – the longer they’re floating and falling the better the chance of those droplets will form a nice crystal.”

That’s Dave Kennedy, a resident of Truckee, a long-time snow gunner who once worked on-property as a snowmaking tech, and who now serves as the stateside representative for TechnoAlpin snow guns, a leading brand of snowmaking machinery manufactured in Italy’s Dolomites – a mountain region with 90% of its pistes, incidentally, comprised of man-made snow.

The act itself — that of making snow, that is — is a ridiculously simple proposition. In fact, any homeowner living in northerly climes with a pressure washer, an air compressor, special fittings to combine the flow of both, and a ready source of electricity, can make snow. Hoist the jets toward the heavens on a below-freezing day, let fly, and you’ll get flakes.

The rest is technique, technology, and scale.

The water comes from wherever a ski resort can get it – most often from lakes, rivers, creeks, and from well water, and sometimes directly from a municipality. If an operator is lucky, all the water it needs comes with the land it either owns or leases. But resorts often have to venture offsite, onto adjacent or far-flung land, to purchase additional water rights.

To cover its slopes with snow, a large resort – say, Heavenly Mountain — requires a physical plant as complex as a small municipality’s water system – which in a sense, it is. In addition to the snow guns, which have become so ubiquitous on area slopes most skiers don’t even notice them – add air compression plants, pumps, hydrants, water coolers, water wells, water reservoirs, a fleet of snow cats to spread the snow across the slopes, and a concatenation of piping to tie the water and air works to the guns, which are dispersed — in Heavenly’s case — over thousands of acres of steep terrain. Increasingly, resorts are investing in automated snowmaking systems, which save them in manpower as well as raw materials – water and air – and theoretically lead to better and more energy-efficient “product.” All the same, Heavenly employs a staff of about 40 full-time snowmakers, whose work is, by definition, extreme: they work in sub-freezing weather with high pressure water accouterment, on the sides of steep slopes and atop 30-foot towers.

Snow guns, or cannons, come in two varieties.

“We now use what we call stick guns to get the water up high in the air, or we use fan guns,” says Kennedy. “With stick guns and fan guns we use a very small amount of air, and we mix it with a bit of the water to get a bit of a crystal forming, and the other droplets are broken up through a nozzle, and they fall. Those crystals that are formed from the air-water mix and are what the water droplets start to re-form around.”

Kennedy is talking about nucleation, the process of crystal-building that starts from a kernel of cold air, and around which an incipient crystal can wrap itself. Projecting those crystals high into the sky using forced air gives them “hang time.” As they float to the ground, they acquire the more intricate branches and plates — dendrites — that lend the snow its floaty quality. The fewer needles, the harsher the ride.

Snowmaking works best in cold, dry, and windless conditions. The key, really, is the humidity; when it’s very low, ambient air temperatures needn’t even dip below freezing to make snow. And water is often cooled prior to being jetted out of the guns to hasten the nucleation process. In marginal snowmaking conditions, snow is gathered into drifts, where the crystals are allowed to cure, or thoroughly freeze, before being spread onto the slopes by snow cats.

The ingredients of snow are very simple – but the sourcing of the ingredients and the distribution of the end product is anything but.


“We’ve got the largest snowmaking system on the West Coast,” Russ Pecoraro,  the former Director of Communications at Heavenly Mountain Resort, told me six years ago. “We can cover 73% of our trails in machine-made snow!”

I’m surprised when Pecoraro, whom I called precisely because of Heavenly’s reputation as the overlord of Sierra snowmaking, launches the conversation with a boast – but he was preaching the party line, no doubt. Heavenly’s snowmaking superiority is a strategic advantage; its secret sauce.

“We can cover an area the size of a football field eight feet deep in the amount of time it would take to play a three-hour game!”

I appreciated the gridiron analogy. After all, Heavenly, which is owned by Vail Resorts, is competing in a no-holds-barred game against its cross-lake rivals, KSL, the owners of the Squaw-Alpine complex. In terms of pure snowmaking capacity, no one even comes close to Heavenly – not even its sister resort, Northstar – and taken together, Vail’s two properties make more snow than every other ski resort in the region combined.

“Nobody can make snow like we can.”

OK, fine. I’m a believer.

“That said, I can’t release the number of gallons we use, or the amount of snow we make, or anything like that.”

Why not?

“It’s not something we can release as a publicly traded company.”

I’ll just have to guess, then.

It takes roughly 180,000 gallons of water to cover an acre of land a foot deep in machine-made snow, according to Kennedy. In a drought year, one foot of snow on bare ground is probably insufficient to cover rocks, tree limbs, or shrubbery (despite a common practice of pruning the slopes during the dry season, by removing vegetation, to create a uniform surface for early season snow).

So let’s assume a depth of two feet of snow per acre, and use 180,000 gallons of water for each acre-foot of snow.

Heavenly advertises 73% coverage of its 4,800 acres of skiable terrain. Multiply that number by 180,000 and then double it (remember that two feet of coverage), and it takes nearly a billion gallons of water to make snow. That seems far-fetched.

In truth, the ski resorts would like you to believe they make snow on their advertised percentage of total ski area, when in fact, they mainly mean the number of groomed runs, which might account for less than half of skiable area (which includes the ungroomed glades and sidehills). In Heavenly’s case, that boils down to roughly 528 acres which, based on water supply and pumping capacity, equals 1,848 acre-feet of snowmaking. That’s about 333 million gallons of water – and in an extremely dry year — such as the 2011-2012 debacle — they’d likely use more. Let’s say 400 million gallons. If true, Heavenly’s annual snowmaking payload could satisfy the water needs of over 11,000 people a year – that’s half of South Lake Tahoe’s year-round population. (Vail Resorts’ annual report says that in the 2013 to 2014 season it used 150 millions gallons of water, most of it from underground, to make snow on 317 of acres.)

I asked Pecoraro the source of Heavenly’s source of snowmaking water. He mentioned Heavenly’s two “lakes,” which he said accounted for most of the supply.

So what are the lakes’ sources, I wondered. I mean, all lakes have inlets.

“We have contracts with some of the local water companies to help fill up those lakes. But a lot of it is caught. We’re kind of reusing the same snow and water year after year.”

Heavenly’s water supply is indeed robust – they’ve got no shortage of water rights — and because the resort straddles both Nevada and California, the resort utilizes a two-state supply chain, pulling water from that network of wells, and supplementing with allocations from both the South Tahoe Public Utility District and the Kingsbury General Improvement District. The wells, of course, represent groundwater, and the groundwater is connected by way of the water table to the year-round and seasonal creeks on Heavenly’s property. Those “lakes” are actually reservoirs, which store 55 million gallons of fresh water.

In 2015, I asked Mammoth Mountain’s Clifford Mann about the water source and snowmaking capacity of the system he built for Dave McCoy in the 1990s. “I don’t talk about water,” Mann told me, and referred me to Mammoth’s marketing department. When reporting a piece about snowmaking for Sierra Magazine in 2015, I spoke to University of Waterloo snow tourism researcher Daniel Scott, who told me that snowmaking operators routinely deny him information about their water consumption. (Scott was the lead author of a 2014 study called “The Future of the Olympic Winter Games in an Era of Climate Change,” which demonstrated that under a high-emissions climate change scenario, only 10 of the past 19 winter Olympic venues will be able to host the games in 2050.)

We know this much: Mann’s crew of 40 snowmakers have their choice of more than 1,000 snowmaking utility boxes mountain-wide to cover 600 acres of Mammoth’s lava rock.


Bob Roberts, the then president of the California Ski Areas Association, was having a rough day. It was just two weeks before Christmas Break of 2012, and the National Resources Defense Council and Protect Our Winters, two environmental non-profits, had issued a 33-page report, Climate Impacts on the Winter Tourism Economy in the United States announcing that climate change had dinged ski resort revenues by 1 billion dollars in the past ten years. More dings were on the way, the report foretold,  as climate continues to wreak havoc with snowfall.

I was probably the tenth journalist who contacted Roberts for a statement.

“Here in California we do have more to say on the subject and a track record to stand on,” he wrote me. “That said, we are not in the dueling press release business.”

Attached to his email was a two-page position statement from the National Ski Areas Association, the voice of the U.S. ski industry.

The tone of the release? Dismissive. “We’re on it,” they implied. “Check out all we’re doing to curb climate change.” They provided a punch list of the initiatives they’d launched, but didn’t wholeheartedly address the issues surfaced in the NRDC report.

A week later, Vail Resorts ran an ad in the New York Times showing skiers frolicking at its various resorts around the country, including Heavenly Mountain and Northstar. The Climate HAS CHANGED, screamed the headline.

Vail CEO Rob Katz submitted an op-ed piece to the Denver Post condemning the media for dog-piling the ski industry in the wake of the NRDC press release.

“Count me in the category of someone who is very worried about climate change,” he wrote, followed close on its heels by “…you can count me out of the group that says we need to address climate change to save skiing.” Skiing will be the last thing on skiers’ minds well before the last dollop of superheated snow hits the fan, implied Katz.

That much is true. But between now and then, his job is to increase shareholder value. And that’s precisely what he’s set out to do, by establishing the biggest water works in North America on each of Vail’s properties.

“I don’t pretend to be a climatologist,” Roberts, told me in a later conversation, when he was feeling more voluble. “We’re not looking at a scenario where our industry says, ‘This is a bunch of hocus; this is phony science.’ We believe it. The question is, how much of it is controllable; how much of it is going to be happening over the next twenty to fifty years. What is that curve going to look like? Obviously our resorts that are making substantial bets on it are betting that it’s going to be a manageable curve.”

A couple of days later, I tracked down Noah Diffenbaugh, the Center Fellow at Stanford’s Woods Institute for the Environment. Diffenbaugh had recently co-authored a climate study published in the science journal, Nature: “Response of Snow-Dependent Hydrologic Extremes to Continued Global Warming.”

Diffenbaugh  repeated what I’d heard all along: “Our work, as has other work before us, suggests shifts to earlier runoff timing both from decreasing snowfall and increasing rainfall, and also from earlier melting of the snow that does fall,” he says. “What we’ve predicted is extremely high winter snowmelt and runoff and extremely low spring snowmelt and runoff.”

In short, Diffenbaugh’s findings mean that California’s water storage system will soon be inadequate to supply drinking water to the state’s citizens. Engineers designed the Sierra’s waterworks assuming snow would linger in the hills and run off come late spring. Now, according to Diffenbaugh, Januarys have essentially morphed into Aprils. All of the water rights in the world and even unlimited snowmaking capacity cannot forestall high temperatures and rain, which will lay waste to the snow on the relatively low-elevation resorts. At the same time, snow researchers have discovered that when light absorbing particulate matter, like dust and soot, invade snowpacks and reduce their reflectivity, they are as much to blame on the diminution of snowfields as warming temperatures. To wit: when the Sierra Nevada goes dry, so does California’s Central Valley as growers let fields go fallow. Winds stir up the dust and deposit them on the mountains, contributing to even earlier runoff.

Meanwhile, resort owners in Tahoe are hedging while they can with prodigious amounts of snowmaking. So integral is snowmaking to their survival, in fact – as are the water rights to supply the raw material for machine-made snow – that they’ve all made significant investments in the past few years to increase output and efficiency of covering their slopes, Northstar style.

Five years ago, KSL announced plans to increase snowmaking by thirty percent. Homewood proposed an additional 78 acres of snowmaking, with an additional 45 to 75 snow guns, which will consume 66 million gallons of water, assuming coverage of an acre-foot). Homewood’s development plans have been stalled by a lawsuit slapped on both the resort and the Tahoe Regional Planning Agency, which claims erroneous assumptions in the Environmental Impact Report (EIR), and accuses the TRPA of turning a blind eye to the environmental ramifications of new development. Even little Diamond Peak increased its snowmaking capacity by 35% in 2011.

It’s not hyperbole to insist water is the lifeblood of ski resorts; with increasing scarcity, it will become more valuable still. The NSAA suit basically said as much. And if you don’t believe NSAA, just talk to the folks at SMI, a U.S.-based manufacturer of snowmaking equipment. They’ve provided a “To Do” list for clients interested in buttressing their futures with snowmaking.




“There’s two ways to view it,” says Kennedy. “As long as we’re careful and take a small percentage of water and don’t impact fish habitat, stream sources, and stream ecology, then we’re fine. The other side is we’re keeping it in watershed and we just are releasing it at a different time by the front gate, I guess you’d say.”

Kennedy is referring both to drawdowns of water sources as well as to the notion of snow as a frozen holding pond, to be released upon melting to Lake Tahoe, and later, to Truckee, Reno, Sparks, and eventually, Pyramid Lake. Taking care not to become overzealous in pumping water onto slopes is most assuredly aided by regulatory agencies who daily monitor water consumption. But no agency has the capacity to monitor ski resorts 24-7, so the resort operators self-monitor.

Perhaps that’s why professional snowmakers and even some hydrologists seem unconcerned about snowmaking’s water consumption; they claim most water returns to the water system by leaching back into soils, or finds its way back to streams, or trickling into snowmaking reservoirs, where it’s recycled – as Pecoraro implied.

The operative word is “most;” it’s true that most of it does. But “most” can mean as little as 51 percent. Experts estimate anywhere from 10 to 15 percent is lost where the water is ejected from a snow gun due to sublimation, a technical term for dissipation. And all snowpacks evaporate, whether natural or machine-made. That’s another 10 to 15 percent lost.

“If you look at the guns going off, you see a large portion of the cloud dissipates and disappears,” says Mike Dettinger, a climatologist at Scripps Institute of Oceanography, who has modeled weather patterns in the Tahoe Sierra.

Conservatively, of every five snowflakes made, one will suffer an undignified death. Translated into water, that’s 20 gallons per 100 gallons used for snowmaking. So if Heavenly is using 400 million gallons of water for snowmaking during thin winters – and those winters will become very, very lean, as we have learned – average loss from sublimation and evaporation equates to nearly 80 million gallons lost to the system.

But most of Heavenly’s snowmaking water comes from the ground, not from lakes or streams. Not only does groundwater take much longer to return to its natural underground reservoir, it’s subject to even more degradation — maybe as much as 40 percent lost to the water system.

And that’s just Heavenly. On the rim of the Tahoe Basin add Northstar, Squaw-Alpine, Diamond Peak and Homewood. Outside the Basin, but within the Tahoe Sierra, another five: Kirkwood, Mt. Rose, Boreal, Sugar Bowl, and Sierra-at-Tahoe.

Assuming Heavenly outguns all other Tahoe resorts, but the others are making gains, it’s likely that their snowmakers consume nearly 1 billion gallons of water in drought years, equating to the loss of 200 million gallons or more. That’s an uneducated guess, because no one has studied the cumulative impact of a region’s water loss due to snowmaking. Assuming that I’m 50 percent accurate, that’s still 100 million gallons of water lost to the system.

In the Tahoe Basin, the Tahoe Regional Planning Agency, the Forest Service, and the Lahontan Regional Water Quality Control Board lay down and occasionally enforce the environmental law; it often falls to grass-roots environmental non-profits to file suit when agencies aren’t rigorous enough in vetting, say, the master plans and environmental impact assessments the resorts must file prior to expansion. And though resorts have become better at policing themselves, and have adopted their own sustainability measures – it behooves them, after all, to manage their environmental footprint from the simple standpoint of controlling costs – it’s unlikely any single agency can police the goings-on across a region as extensive as the Tahoe Basin, much less every aspect of a resort’s operations. Agencies don’t often compare notes. The TRPA has been sued for lax oversight in the past. Because the regulatory community and the ski area employees, and the journalists, and the burghermeisters live in the same community, and because their kids play on the same soccer teams, and because there’s so much at stake economically…well, a certain amount of collusion cannot help but exist. Even among fierce competitors. (In other words, the community is small, incestuous, and they’ve got one another’s back. That winter I approached TRPA’s PR officer for water and energy data from snowmaking. I assumed the PR officer would route the query internally. Instead, she forwarded my request to Squaw Valley’s marketing manager, who contacted me through email — and cc’d both the President of Squaw-Alpine and the COO of Vail’s Northstar resort.)

Heavenly Mountain has been slapped in the past with remediation orders from Cal EPA, for sullying the water quality of Heavenly Valley Creek – a result of overly sedimented runoff resulting in turn from denuding them of vegetation for snowmaking purposes. Contouring ski trails leads to erosion, which leads to sediments in streams, which leads to the diminution of Lake Tahoe’s clarity.

The Ski Area Citizens’ Coalition, an environmental non-profit stewarded by South Tahoe’s Sierra Nevada Alliance, is an independent watchdog group that grades ski areas on their environmental practices. Snowmaking is one of the criteria – but areas are graded solely on acreage added in a given year, and not on water consumption – nor is there a cumulative grade for resorts sharing a common region, such as those in the Tahoe Basin.

In the Alps, snowmaking is considered a luxury use of water. The International Commission for the Protection of the Alps, or CIPRA – a multi-sectoral NGO — has resisted  new snowmaking installations because of “unacceptably high levels of water and energy consumption.” In the short term, snowmaking may create a virtuous cycle: snow begets skiers begets dollars begets artificial snow. Seen another way, snowmaking is a disastrously harmful practice. “The irony with making snow,” Auden Schendler, Aspen Skiing Company’s vice president of sustainability, told me, “is that you’re basically cannibalizing the climate.”

When regulatory agencies and grassroots environmental groups haven’t done the job in the past, citizens have taken matters into their own hands. In the Northeast U.S., where drought conditions have been more marked than in the West, the Public Trust Doctrine to impose restraining orders on ski area water consumption. Autumnal water drawdowns to fill snowmaking reservoirs, the plaintiffs have claimed, damage sensitive riparian habitat, including fisheries, when they can least afford it.

“The issue of water as a zero-sum game hasn’t been discussed on a regional level, says the Sierra Business Council’s Steven Frisch, “but it ought to be.”


Transporting the water to guns, and from guns to the slopes requires an enormous amount of electricity and fuel.

According to Dave Kennedy, the modern snow gun consumes between 1,000 and 2,000 kilowatt hours per acre foot of manufactured snow. That’s about the same CO2 output as four barrels of oil per kilowatt hour.  With Heavenly’s 1,848 acre-feet of snow, that’s the equivalent of 530 passenger vehicles a year, according to the EPA. Combined with the carbon load of the snow cats shoving machine-made snow up and down slopes, the snowmobile emissions from snowmakers, the numbers may not be startling, but they’re not insignificant – and they may be low. Daniel Scott analyzed the energy consumption of Maine’s Sunday River Ski Area, a small resort roughly an eight of the size of Heavenly, and found that it generated 10,022 tonnes of CO2 emissions annually — the equivalent of the energy expenditures of 3,600 households.

Ski areas in the Tahoe Basin have been more proactive in addressing issues of climate change than water consumption. The California Ski Industry Association, for example, supported California’s Assembly Bill 32, the Global Warming Solutions Act, which set CO2 emission targets for the year 2020 on a state-wide basis. Tahoe resorts have instituted CO2 emissions mitigation measures, or more popular, offsets. Most are revamping their snowmaking operations by replacing the more energy consumptive air-water guns with fan guns, which have onboard air compression, obviating the need to pump air from a large physical plant. Even so, Heavenly received a “D” from the Ski Area Citizens Coalition climate change practices, and a “C” overall for collective environmental practices, but this grade might not be reflective of Vail’s overall program.

But that’s just Heavenly.

“There simply hasn’t been a good mechanism for the kind of regional climate planning we need to do,” says the Sierra Business Counsel’s Frisch.


“Here’s the devil’s advocate argument: You’re probably doing more good than harm. When you have a drought and you don’t harvest the water, and freeze it – and keep it in a dam – what are the salmon going to do?”

Meet Graham Kent, an old climbing partner, who was raised in Tahoe and migrated to San Diego, where he received a Ph.D in geophysics from the Scripps Institute of Oceanography. He returned to the Tahoe Sierra some years back and currently serves as Nevada’s chief seismologist.

“So if you blow a bunch of snow on a ski resort, and it melts and provides throughput to keep the water going, you actually might be doing some good there.”

This is a much bandied-about argument in support of snowmaking as a kind of geoengineering intervention to combat the premature runoff predicted by climatologists.

It’s an interesting idea — and it could work, if the CO2 produced in the snow’s manufacture doesn’t negate its benefits to water storage. Here’s the thing: if the changing climate brings more rain to the mountains during the mid-winter months, snowmaking asa  storage solution in a warm-ish winter would fail. And rain-soaked snow would be washed downstream.


According to the Environmental Protection Agency, less than one percent the planet’s water is available for consumption, and it’s becoming scarcer by the year.

The notion of water and air as a commons is already well-established, and the public trust doctrine will, inevitably, find traction in the coming water wars. Whether the appropriation of a resource as fundamental to human life as water for the recreation of the relatively well-off, is a matter for ethicists to debate. And indeed, all data are debatable. Enough evidence and precedents exist, however, to counter the argument that the case against snowmaking is mere casuistry. That the state of the snowmaking art is improving there is no doubt. But so are precious resources in decline.

Although the ski industry would like its fans to believe they’re doing the right thing by the environment, the best intervention would be to cease the use of climate modification. Doing so would disrupt the ski industry, and with it, local economies built around ski tourism, but the resort operators have already anticipated climate-related drop in revenues and have expanded recreation offerings into the shoulder seasons. Still, without skiing, the economic cost to entire regions would be enormous. At least one San Francisco State University economic study put the value of Tahoe’s snow-based economy at a half-billion dollars.

But does the environmental cost to the snowpack outstrip the monetization of the artificial stuff? Thus far, no individual or group has called into question the snowmaking water loss of water and CO2 emissions region-wide.

Says Frisch, “One of the ethical questions I think should be asked in the Sierra Nevada is what are the impacts when we as a species attempt to intervene in this global cycle – how do we know what the consequences of that are?”