Fire menaced some of the most expensive vineyard land in North America on Monday, as flames raged out of control towards Napa Valley's Pritchard Hill.

The Hennessey Fire in Napa was one of several that broke out in the state after an apocalyptic weekend of weather in California. Several threaten fine wine regions, including a large fire in Monterey County that broke out Sunday night, two small fires in the Santa Cruz Mountains and a large fire with evacuations in Contra Costa County.

Let me write in first person for a moment: I've lived in California for more than two decades and I've never seen anything like Sunday. When I woke up on Sunday morning in normally cool San Francisco, the sky was an angry orange, the temperature and humidity was tropical (a local chef tweeted that it reminded her of her native Thailand), and lightning was visibly crackling every few seconds. It looked like a Hollywood prelude to an alien invasion and/or the end of the world.

After a typically completely dry summer turned all the state's native vegetation into kindling, most of the state had a record heat wave for two days, joined all day Sunday by that near-continuous dry lightning. We did have some thunderstorms, which was weird – rain is exceedingly rare in California in August, which is why grapegrowing is famous here. But there wasn't much rain and there was a lot of lightning, starting fires all over the state.

Napa County actually has two fires as of Monday afternoon, but only one – the Hennessey Fire – menaces vineyards at the moment. It started on the north side of State Highway 128 in the east side of the Valley, about five miles due east of Rutherford. Fortunately Lake Hennessey sits between the fire and Silverado Trail less than three miles away.

However, the Hennessey Fire leapt south over Highway 128 on Monday morning – the road is currently closed in both directions – and began burning its way toward the sources of some of the most expensive wines in the world.

Chappellet Winery, the pioneers of Pritchard Hill winegrowing, reportedly was evacuated Monday morning; I have been unable to confirm that, though the winery did tweet a photo of smoke approaching the vineyard.

Other wineries that make wine from Pritchard Hill vineyards include Colgin Cellars, Brand, Continuum, Bryant Family, Gandona and Ovid. You could buy a new car, or you could assemble a horizontal tasting of Pritchard Hill wines.

Fortunately we have learned from past fire seasons that vineyards are fairly effective firebreaks, and still-rural Pritchard Hill does not have as many buildings as nearby Silverado Trail. As of Monday afternoon, the fire had spread to 750 acres and was 0 percent contained.

Pritchard Hill has gained prominence in recent years among collectors in part because of the high scores from critics for the wines, but also because of its appeal to the Napa consumer's love of scarcity. Though it is a geographic landmark, it is not an American Viticultural Area because Chappellet trademarked the name to use on its own wines. Thus, the only way to know if a wine is from Pritchard Hill is to know it.

Pritchard Hill's vineyards range from 800 feet to 2000 feet in elevation, making it a tricky place to fight fires. The hill is named after Charles Pritchard, who grew Zinfandel and Riesling there starting in 1890. It didn't enter the modern era of viticulture until the Chappellets bought their land in 1967. Their success in making Cabernet Sauvignon, with richness and depth, inspired people to spend increasingly large amounts for vineyard land nearby. Winemaker Philippe Melka once told Wine Enthusiast that Pritchard Hill offers "the best of both worlds: Oakville sophistication with the extra intensity of a hillside".

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