The more than 67,000-acre Glass Fire in early autumn wrought devastation in the heart of Northern California’s iconic wine country, damaging or destroying nearly 30 wineries while affecting as many as 80% of Napa Valley vineyards and causing industry losses approaching $500 million, according to published estimates.

The fire that started Sept. 27 near Calistoga and St. Helena affected numerous Upvalley wineries and vineyards, including Fairwinds Estate Winery, Sterling Vineyards, Schramsberg Vineyards, Castella di Amorosa, Burgess Cellars, Chateau Boswell, Calistoga Ranch and the iconic Meadowood resort, according to news reports.

“It’s very bad,” Fairwinds Estate co-owner Brandon Chaney told the Napa Valley Register. “We lost our bottling line. We also lost our brand new optical sorter that was delivered from France two weeks ago.

“The only silver lining is that we have a 22,000-square-foot wine cave,” he said. “We suspect that everything is safe inside.”

In all, the fire had damaged or destroyed 1,837 residential, commercial and other buildings in Napa and Sonoma counties and was mostly contained as of Thursday, reported the California Department of Forestry and Fire Protection.

In many cases, it’s not just the flames that are problematic, but the ash and smoke exposure. The risk increases with prolonged or repeated exposure to heavy fresh smoke, whose chemical compounds can permeate the skin of grapes and give the resulting wine an ashtray-like flavor.

Related:Napa’s worst case scenario: Some 80% of cabernet lost to fire, smoke

Already a concern

Winegrape growers were already facing likely smoke taint issues after the 363,220-acre LNU Lightning Complex rolled through the region in late summer, destroying or damaging over 1,500 structures while killing five people and injuring five others, Cal Fire reports.

In September, the Novato, Calif.-based Ciatti California Grape Market Report commented: “Even though, in many cases, there was no direct physical damage to vineyards and processing facilities, smoke exposure concerns had a substantial effect on our industry and consequences are being felt by mainly Coastal growers and the bulk wine market.”

Philippe Melka, a winemaking consultant to three dozen high-profile wineries, estimated to Bloomberg News that 80% of Napa Valley vineyards may have been affected by fires and smoke this year.

“Fresh smoke is what we’re worried about,” Glenn McGourty, a University of California Cooperative Extension emeritus viticulture advisor, said during a recent webinar. “When smoke inundates a vineyard from a rapidly spreading fire, that’s when we’re going to have problems. Old smoke from some distance … makes our lives miserable, but it probably won’t affect the fruit. Old smoke is mostly suspended particulates.”

Related:With wildfire smoke, how ominous is the outlook?

More than half the Napa Valley’s grapes are cabernet, a high-value wine, and many of those grapes were still on the vine when the Glass Fire started. Some producers have decided not to bother picking them, and in other cases, evacuations hampered efforts to harvest grapes.

While the full extent of the fire’s economic impacts won’t be known until next year, Turrentine Brokerage partner Brian Clements told the North Bay Business Journal that a 20% drop in crop value because of smoke taint would equate to a $473 million loss from the past five-year average.

Labs have been inundated this fall with grapes they’re testing for smoke taint. While it usually only takes a couple of days to get results back, labs are currently facing a six- or seven-week backlog, McGourty said. State and university labs have offered to help test grapes.

Worst in history

California is now enduring what authorities are calling its worst fire season in history. The state hit a fearsome milestone: 4 million acres burned by more than 8,200 wildfires this year with 30 lives and hundreds of homes lost, according to state officials.

Among other major blazes was the Zogg Fire in western Shasta County, which burned 56,338 acres, destroyed or damaged 231 structures and caused four fatalities, according to Cal Fire.

Growers are already taking stock of crop damage and making needed facility repairs after wildfires in California, Oregon and Washington this summer charred hundreds of square miles of rangeland and timber, including high-value allotments on public land.

Blazes this year burned a university ranch in Santa Cruz, destroyed livestock and bees near Vacaville and shrouded nearly the entire state in thick smoke and ash for weeks. State officials opened 17 fairgrounds as local resource centers, and they housed more than 365 animals between them, the California Department of Food and Agriculture reported.

Farmers say smoky skies have slowed progress of California’s raisin crop, as it’s been taking up to two weeks longer than usual to dry grapes in San Joaquin Valley vineyards, according to the California Farm Bureau Federation. The smoke won’t affect raisin quality, but the delay it causes could reduce the size of the crop, the CFBF explained.

The state’s fire season may not end soon, as the federal Climate Prediction Center sees a likelier-than-normal chance that dry and warm conditions will persist through the end of 2020.

Wildfire country

Fires are becoming an annual occurrence in the northern San Francisco Bay Area’s wine country, which has suffered a series of devastating infernos in the last four years. In 2017, more than 2 dozen wineries were damaged or destroyed by fire. In the following year, smoke from the Mendocino Complex Fires destroyed the market for an estimated $41 million in wine grapes grown in vineyards near burned areas.

Anticipating this year’s fallout, California Association of Winegrape Growers president John Aguirre issued a statement in early September: “Unless specified in a contract, no buyers should believe they are entitled to reject a grower’s grapes based on concerns over smoke damage without corroborating evidence to indicate those grapes have, indeed, been damaged.”

As they watch, grape growers and wine lovers around the country can only offer their sympathies. In New York, the folks overseeing vineyard crop development at Cornell University Agritech Lab wrote in their most recent newsletter: “California growers have been robbed of the healthy distraction of the annual harvest, a destabilizing and debilitating uncertainty on top of all the others. We on the East Coast count our blessings and send our support.”

[Freelance writer Lee Allen contributed to this report.]