The remains of the guest houses at Calistoga Ranch smoulder after the Glass Fire passed through

The scale of wildfire devastation to Napa's world-famous wine region was laid bare Wednesday as firefighters reported minor progress battling the flames and a separate California blaze claimed its latest victim.

At least a dozen Napa wineries and vineyards were burned as the so-called Glass Fire erupted this week, with the scorched area now spanning almost 50,000 acres (20,200 hectares) and the inferno still just two percent contained.

A stone building used for storage and as a laboratory at the Castello di Amorosa winery in Napa Valley was left in ruins, as smoke rose from the scorched ground at vineyards and buildings were blackened by soot across the region.

"Our spirit is strong. We've been through some challenging times recently because of coronavirus and other fires," said hospitality director Madeleine Reid, standing beside the smoldering remains of the faux-medieval winery's farmhouse.

"We are hoping and praying that everything is going to be okay for our neighbors," she added. "We're just so grateful for the firefighters."

Tens of thousands of residents have been evacuated from the vicinity of the fire, which extends into neighboring Sonoma.

Calistoga—a picturesque jumping-off point for wine tours at the top of the valley—remained deserted and surrounded by flames Wednesday.

The rubble that was once the main building at Calistoga Ranch is pictured following damage by the Glass Fire

"It's not awesome," said Mayor Chris Canning. "I guess the positive side of this is that the fire is not in the city. It is all around us."

At least 80 buildings have been destroyed by the fire in total, but thousands more are threatened, according to fire officials.

'California is burning'

California is experiencing a record-breaking fire season, with five of the state's six biggest blazes in history currently burning, and nearly four million acres scorched.

Some 200 miles north of Napa, the Zogg Fire claimed its fourth fatality—a man airlifted to the hospital with burns on Sunday, said Shasta County Sheriff Eric Magrini.

That brings California's death toll this year to 30.

Evacuations have been complicated by the coronavirus, which has hit the Golden State hard with more than 819,000 confirmed cases.

Smoke rose from scorched ground beside vineyards and soot-blackened wineries in Napa Valley

State officials have pointed to as a significant cause of the wildfire surge, but President Donald Trump used Tuesday's presidential debate to repeat his call for more "," including removal of dead trees.

"Every year, I get the call: 'California is burning. California is burning,'" said the president. "If that was cleaned, if you had forest management, you wouldn't be getting those calls."

Climate change amplifies droughts which dry out regions, creating ideal conditions for wildfires to spread out-of-control and inflict unprecedented material and environmental damage.

'Make it through'

At the Glass Fire in wine country, some 2,000 firefighters were battling Wednesday to tamp down the flames ahead of another expected strong wind event, similar to the one that caused the fire to erupt Sunday night.

Firefighting efforts have been hampered by thick smoke, preventing aircraft from dropping water or retardant.

Cars with paint melted off their hoods and front tires melted away could be seen in Napa Valley after wildfire struck

"We have little containment and there are many hazards still left behind," warned Sonoma County Sheriff Mark Essick at a briefing Wednesday.

He added that upcoming weather "is not necessarily going to be favorable for us. So please stay alert."

It is too late for the Chateau Boswell winery, left in ruins with yellow tape hung across the gate of a drive along the famed Silverado Trail.

A short distance away at the Trailside Inn Bed and Breakfast, the skeletal remains of a bus converted into an RV sat in a smoldering patch, near a vintage Packard car with paint melted off the hood and its front tires melted away.