Dry, hot and windy conditions are threatening to expand California’s largest wildfires, which so far are burning in largely rural areas.

The fires, which have killed 12 people and burned an area almost as big as Rhode Island, have hit the tourism industry around Yosemite National Park but left agricultural areas mostly unscathed.

“While the fires have been devastating and ferocious — our Mendocino wine industry has little impact,” said Bernadette Byrne, executive director of Mendocino WineGrowers in Northern California.

The blazes have forced thousands to evacuate homes and blackened about 1,000 square miles (260,000 hectares) of forests, hillsides and pastures, according to the California Department of Forestry & Fire Protection, known as Cal Fire. That’s almost triple the area that had burned in the state by this time last year.

Unlike fires that ripped through California wine country in 2017, authorities have not blamed any of this year’s blazes on utility power lines. Cal Fire has determined that one of the largest blazes — the Carr fire in Northern California — was sparked by a mechanical failure of a vehicle, said Heather Williams, a spokeswoman for the agency. The Mendocino blazes, which have grown into the largest in state history, remain under investigation, she said.

One industry that has been battered is tourism — particularly near Yosemite, which for weeks has been largely closed to visitors as firefighters battle a nearby blaze. It could not have come at a worse time for hotels and businesses near the park, which make most of their money in summer.

Dylan Shull, who manages two hotels, the Best Western Plus and the Monarch, said the properties near the park are usually fully booked at peak rates of $200 to $289 from June through August. These days, they’re more than half empty, offering rates of $100 to $189 a night, Shull said by telephone.

“The tourism is pretty much dead,” Shull said. “We’re essentially competing for the firefighters and emergency personnel.”

Tourism officials are already planning to use the fall, typically a slower season, to make up for the summer calamity. They’re developing a campaign called “Yosemite Now” to educate people and draw them back, said Therese Williams, spokeswoman for Visit Yosemite Madera County. Hotels may reduce rates and offer other specials, she said by telephone.

Wine Country

Two-hundred and fifty miles (400 kilometers) northwest, a separate fire in Mendocino County forced two wineries — Fetzer Vineyards and Vintage Wine Estates — to close for several days. But flames didn’t hit the vineyards, Byrne said. The fires have moved east, and the growers don’t expect grapes to be tainted by smoke, she said.

Exceedingly thick smoke can ruin grapes, making wine “smell like an ashtray,” said Kurt Schoeneman, owner of Ferrington Vineyards, which produces varietals including pinot noir, chardonnay and sauvignon blanc in Boonville, California.

While grapes have been spared, grazing and timberland have suffered in Mendocino County, said Dave Kranz, spokesman for the California Farm Bureau Federation. There have also been reports of damage to pear orchards and vineyards further east, in Lake County. It’s too soon to know if smoke has damaged grapes there, he said.

“We’ve been getting some smoke and it’s not too bad,” Schoeneman said by telephone.

The devastating fires of 2017 are continuing to roil California’s giant utilities. PG&E Corp. faces as much as $17.3 billion in potential liabilities from last year’s blazes in wine country. The company has raised the prospect of bankruptcy as it lobbies the state to ease its burden. Edison International may have about $3 billion in costs related to December’s fires in Ventura and Santa Barbara counties, according to Bloomberg Intelligence.