- Napa Valley Vintners has reached out to all its members and received updates from more than 120 of them.
- In addition to the five in Napa that sustained significant or total losses, at least 11 reported damage to their winery, outbuildings or surrounding vineyards.
- Signorello Estate, a family-owned winery on Napa's Silverado Trail, was destroyed in the Atlas Peak Fire.
At least six wineries in northern California have sustained total or very significant losses as fires continue to blaze through the region, according to the Napa Valley Vintners and the Sonoma County Vintners.
Some 22 fires have burned more than 170,000 acres in California, torching more than 3,500 homes and commercial structures, according to the California Department of Forestry and Fire Protection. At least 21 people have died and many have been reported missing.
Napa Valley Vintners has reached out to all its members and received updates from more than 120 of them. Five in that county sustained significant or total losses, and at least 11 reported damage to their winery, outbuildings or surrounding vineyards.
The association declined to disclose the names of those affected.
In Sonoma County, Paradise Ridge Winery burned down. There have been reports of others, but Michael Haney, director of membership for the Sonoma County Vintners, could not confirm them Tuesday. The situation remains fluid, he said.
As of Wednesday, Paradise Ridge remained the only known winery to have burned down in the area, Sonoma County Winegrowers President Karissa Kruse said in a statement. The organization has not been able to receive accurate updates from Sonoma Valley because most of the area remains under evacuation orders, she said.
Rene Byck, vice president and co-owner of Paradise Ridge, told CNBC the wine-making facility, tasting room and event center are completely lost. His parents bought the land in 1978 and opened the winery in 1994.
"That's pretty devastating. But to be honest, our neighbors here who lost their homes – and the whole Fountain Grove community, that's more concerning for me and our family than the winery," he said.
"We feel like we can rebuild the winery and maybe even make it a better place. But it's the community, the people who lost lives and houses and lost almost everything, those are the people you need to support."
The Napa Valley numbers could change, as the association has yet to hear from some members in the most vulnerable areas of Napa County. Some owners have not yet been able to reach their properties and assess the damage.
Fires are still burning, people have lost their homes and some have evacuated, making it hard to even think about getting to work, Kruse, the Sonoma County Winegrowers president, told CNBC's "Squawk Alley" on Wednesday.
Signorello Estate, a family-owned winery on Napa's Silverado Trail, was destroyed in the Atlas Peak Fire. The winemaker, winemaking and vineyard teams were at the winery trying to fight the fire but retreated when it overcame the building, wrote owner and co-winemaker Ray Signorello Jr. in a Facebook post Tuesday.
The winery's 25 employees are safe, he said.
This year's grapes have been harvested and were inside fermentation tanks; staff have been so far unable to access the property and check on them and the vineyards, Signorello's sommelier Ronald Plunkett told CNBC on Tuesday.
Signorello's Chardonnay vines are 38 years old, Plunkett said. If those are burned, the winery must plant new ones. It would take about five years for those to produce wine. And even then, the resulting wine would not taste the same.
"It's like getting punched in the stomach," he said. "I just got back from vacation, looking forward to going back to work because ... it's not work to me. It's a passion."
The winery produces less than 5,000 cases of wine per year, he said, and the employees are like family.
"This is devastating to us because this is kind of our home," he said.
Harvest is underway in the region, and Napa Valley Vintners estimates 90 percent of the grapes were picked before the fires started on Sunday. Of those remaining on vines, almost all are Cabernet Sauvignon, and the association's winemakers do not expect smoke from the fire to affect them because the variety is thick-skinned and ready for harvest.
Haney said the same is true in Sonoma County. Many growers in safe zones picked what's left on the vines, including Chardonnay, on Wednesday, Kruse said in a statement.
The thickness of skin on grapes likely affects how rapidly smoke is stored, said Justine Vanden Heuvel, associate professor of enology and viticulture at Cornell University. Winemaking techniques can affect how smoky the final products taste. Plus, smoke taint tends to be less noticeable in wines that are more complex and are stored in oak barrels, such as Cabernet Sauvignon.
Vineyards should mostly be spared since they're great fire breaks, Jean Hoefliger, winemaker at Alpha Omega, told CNBC's "Power Lunch" on Wednesday. Grass is usually the only thing that can burn, he said, and even then, farmers mow it and till the soil.
"As soon as a fire reaches a vineyard, usually it stops because the plant itself is green material and there's really nothing to burn," he said.
Overall, Napa Valley Vintners said, it is too soon to say how the fires will affect this year's vintage or estimate their economic impact on the region's wine industry. Even wineries that may not have been burned are closed. Some names include Beringer Vineyards, Cakebread Cellars, Hess Collection, Joseph Phelps Vineyards and Opus One Winery.
For its part, Signorello has about 500 members who subscribe to its wine program, Plunkett said. The winery has received an outpouring of sympathy from members and neighbors.
The Sonoma County Vintners' office has been "inundated" with support and well wishes from people in the U.S. and even outside the country, Haney said.
"You can't imagine how wonderful and helpful it has been to all of us," he said. "And I want to say thank you."
-CNBC's Aditi Roy and Megan Hawkins contributed to this story