ST. HELENA, Calif. – Last September, wildfire broke through one of Dario Sattui’s Napa Valley wineries, destroying millions of dollars in property, equipment and 9,000 cases of wine.

November brought a second disaster: Mr. Sattui discovered that the precious Cabernet grape harvest that survived the fire had been ruined by the smoke. There would be no 2020 vintage.

An insanely dry winter led to a third misfortune: in the spring, the reservoir in another of Mr Sattui’s vineyards was as good as empty, which meant that little water was needed to irrigate the new harvest.

Finally, in March, the fourth blow came: Mr Sattui’s insurers said they would no longer cover the winery that had burned down. No other company would either. In the insurance field, the winery will enter the burning season this year, which experts have forecast to be particularly intense.

“We were hit in every possible way,” said Mr. Sattui. “We can’t go on like this.”

In Napa Valley, the lush heartland of America’s high-end wine industry, climate change spells calamity. Not externally: On the main street that leads through the small town of St. Helena, tourists still flock to wineries with elegantly furnished tasting rooms. At Goose & Gander, where the lamb chops are $ 63, the queue for a table is still falling on the sidewalk.

But get off the main road, and the vineyards that made this valley famous – where the mix of soil, temperature patterns, and rainfall used to be just right – are now surrounded by burnt-out landscapes, dwindling water supplies, and increasingly nervous winemakers with it get worse.

Desperation has led some growers to spray sunscreen on the grapes to prevent roasting, while others water with purified wastewater from toilets and sinks because the reservoirs are dry.

Your fate matters even to those who cannot distinguish a Merlot from a Malbec. Napa has some of the most expensive arable land in the country, selling for up to $ 1 million per acre; A ton of grapes is two to four times as much as anywhere else in California. If there’s one corner of American agriculture that has both the means and the incentive to outsmart climate change, it’s here.

But so far, the experience of winemakers has shown the limits of adaptation to a warming planet.

If heat and drought trends worsen, “we are probably out of business,” said Cyril Chappellet, president of Chappellet Winery, which has been operating for more than half a century. “We’re all out of business.”

The Stu Smith Winery is at the end of a two-lane road that winds up Spring Mountain west of St. Helena. The drive requires some concentration: the 2020 glass fire burned the wooden posts that held the guardrails, which now lie like discarded ribbons on the edge of the cliff.

In 1971, after graduating from the University of California at Berkeley, Mr. Smith bought 165 acres of land here. He named his winery Smith-Madrone after the orange-red hardwoods with waxy leaves that surround the vineyards he has planted. For almost three decades, these vineyards – 14 hectares of Cabernet, seven hectares each of Chardonnay and Riesling, and a few Cabernet Franc, Merlot and Petit Verdot – were untouched by forest fires.

Then, in 2008, smoke from nearby fires first reached his grapes. The harvest continued as usual. Months later, after the wine had matured but before it was bottled, Mr. Smith’s brother Charlie noticed something was wrong. “He said, ‘I just don’t like the way the reds taste,'” said Stu Smith.

At first, Mr. Smith resisted the idea that something was wrong, but eventually took the wine to a laboratory in Sonoma County which found that smoke had penetrated the skin of the grapes and affected the taste.

What winemakers referred to as “smoky flavor” is now threatening Napa’s wine industry.

“The problem with the fires is it wasn’t near us,” said Mr. Smith. Smoke from distant fires can rise for long distances and there is no way a grower can prevent it.

Smoke is primarily a threat to red wines, the skins of which give the wine its color. (In contrast, the skins of white grapes are thrown away, and with them the smoke residue.) Reds also have to stay on the vine longer, often well into October, exposing them to fires that usually peak in early autumn.

Winemakers could switch from red to white grapes, but this solution clashes with market demands. Napa white grapes sell for around $ 2,750 per ton on average. In contrast, red wines in the valley average about $ 5,000 per ton and more for Cabernet Sauvignon. There is a saying in Napa: Cabernet is king.

The damage in 2008 turned out to be a harbinger of much worse. Mist from the glass fire filled the valley; so many winemakers tried to test their grapes for the smell of smoke that the processing time in the next laboratory went from three days to two months.

The losses were overwhelming. In 2019, growers in the county sold $ 829 million worth of red grapes. In 2020, that number dropped to $ 384 million.

Among the victims was Mr. Smith, whose entire harvest was affected. The most visible legacy of the fire is now the trees: the flames not only scorch the madrons that gave Mr. Smith’s winery his name, but also the Douglas firs, the brown oaks and the laurel trees.

Trees burned by forest fires do not die instantly; some linger for years. One afternoon in June, Mr. Smith was inspecting the damage in his forest and stopped at a Madrone which he particularly liked but whose chances were not good. “It’s dead,” said Mr. Smith. “It just doesn’t know yet.”

Across the valley, Aaron Whitlatch, director of winemaking at Green & Red Vineyards, got into a dust-colored jeep to drive up the mountain to demonstrate what heat does to grapes.

After negotiating steep switchbacks, Mr. Whitlatch reached a line of vines with delicate Sirah grapes covered with a thin layer of white.

The week before, the temperatures had exceeded 100 degrees and the employees sprayed the vines with sunscreen.

“Prevent them from getting burnt,” said Mr. Whitlatch.

The strategy hadn’t worked perfectly. He pointed to a bunch of grapes at the top of the peak that had been exposed to the sun during the hottest hours of the day. Some of the fruits were black and shriveled – and turned into absurdly expensive raisins.

“The temperature of this cluster has probably reached 120,” said Whitlatch. “We were set on fire.”

As the days get hotter and the sun more dangerous in Napa, winemakers are trying to adapt. A more expensive option than sunscreen is to cover the vines with shade cloth, Mr. Whitlatch said. Another, even more costly, tactic is to replant rows of vines so that they are parallel to the sun and absorb less heat during the warmest part of the day.

At 43, Mr. Whitlatch is a brandy veteran. In 2017, he was assistant winemaker at Mayacamas Vineyards, another Napa winery, when it was burned by a series of forest fires. This is his first season at Green & Red, which lost its entire crop of reds to smoke from the glass fire.

After that fire, the winery’s insurer wrote to owners Raymond Hannigan and Tobin Heminway listing the changes needed to reduce the risk of fire, including updating the breaker panels and adding fire extinguishers. “We spent thousands and thousands of dollars modernizing the property,” said Hannigan.

A month later, the Philadelphia Insurance Companies sent the couple another letter in which they canceled their insurance anyway. The explanation was brief: “Ineligible risk – the risk from forest fires does not comply with the current drawing guidelines.” The company did not respond to a request for a statement.

Ms. Heminway and Mr. Hannigan could not find cover with any other airline. California lawmakers are considering bill that would allow wineries to obtain insurance through a state high-risk pool.

But even if that passes, Mr. Hannigan said, “It won’t help us this harvest time.”

Just south of Green & Red, Mr. Chappellet stood in the middle of the hustle and bustle as wine was being bottled and trucks were being unloaded. Chappellet Winery is the picture of efficiency on a commercial scale, producing around 70,000 cases of wine a year. The main building, which his parents built after buying the property in 1967, is like a cathedral: Huge wooden beams rise up and protect rows of oak barrels that mature Cabernet worth a fortune.

After the glass fire, Mr. Chappellet is one of the lucky ones – he’s still insured. It only costs five times what it was last year.

His winery now pays more than $ 1 million a year, up from $ 200,000 before the fire. At the same time, his insurers cut the amount of cover they were willing to pay by half.

“It’s crazy,” said Mr. Chappellet. “We can’t stand that in the long run.”

There are other problems. Mr. Chappellet pointed to his vineyards where workers were cutting grapes from the vines – not because they were ready to harvest, but because there wasn’t enough water to keep them growing. He estimated that this would reduce his harvest by a third this year.

“We don’t have the luxury of giving them the normal amount they would need to be really healthy,” said Chappellet.

To demonstrate why, he drove up a dirt road and stopped at the two reservoirs that fed his vineyards. The first was a third full; the other, directly above, had become a barren pit. Instead, there was a pipe on the dusty lake bed that once pumped water out.

“This is the disaster,” said Mr. Chappellet.

When spring came this year and the reservoir on Dario Sattui’s vineyard was empty, his colleague Tom Davies, president of the V. Sattui winery, drew up a backup plan. Mr. Davies found Joe Brown.

Eight times a day, Mr. Brown pulls up to a loading dock in Napa City’s plumbing department, fills a tank truck with 3,500 gallons of purified sewage, and drives 10 miles to the vineyard, then turns and does it all over again.

The water, drawn from household toilets and drains, sifted, filtered, and sanitized is a steal at $ 6.76 per truckload. The problem is transportation: each load costs Mr. Davies about $ 140, which he thinks will add $ 60,000 or more to the cost of running the vineyard this season.

And that assumes Napa officials continue to sell sewage that could theoretically be made potable. As the drought worsens, the city may decide that its residents need them more. “We’re nervous that Napa plumbing will stop saying water at some point,” Davies said.

After driving past the empty reservoir, Mr. Davies stopped on a hill overlooking the vineyard.

If Napa gets away with no major forest fires for another year or two, Davies believes insurers will return. The smoke stain and lack of water are more difficult to solve.

“It’s early days to talk about the decline of our industry,” said Mr. Davies, looking out over the valley. “But it’s certainly a problem.”