A California wildfire raging in the Cascade range has claimed three lives, while a separate blaze has prompted mass evacuations and spread turmoil to the famed wine-producing regions of Napa and Sonoma counties.

Monday’s three fatalities in the Zogg Fire in Shasta County, which erupted on Sunday near Redding, north of San Francisco, were reported by the California Department of Forestry and Fire Protection.

They were all civilians.

Elsewhere, California’s world-renowned vineyards in the Napa and Sonoma counties are under threat as a wind-driven wildfire rages for a second day.

An estimated 48,500 Sonoma County residents, including some in parts of the city of Santa Rosa, have been told to evacuate.

In one notable property loss, the castle-like Chateau Boswell winery in St Helena, a familiar landmark along the Silverado Trail road running the length of the Napa Valley, went up in flames on Sunday night.

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As of Monday (local time), a blaze dubbed the Glass Fire had spread across 4450 hectares of rolling grassy hillsides and oak woodlands, fanned by high winds and fuelled by dry scrub.

The fire erupted before dawn on Sunday near Calistoga, in the heart of the Napa Valley, about 120 kilometres north of San Francisco. By the afternoon, it had spread across 800 hectares.

By Monday, the blaze had merged with two others into a conflagration straddling western Napa County and an adjacent swath of Sonoma County.

The Glass Fire burns a hillside above Silverado Trail in St Helena, California, on Sunday, US time. Photo: AAP

Some 5000 Napa County residents were under evacuation orders or advisories on Sunday, including parts of St Helena, Deer Park and Angwin.

No injuries have been reported in the Glass Fire, the cause of which was under investigation.

Santa Rosa Fire Chief Anthony Gossner said the blaze was burning mostly through overgrown scrub in areas have seen little or no wildfire activity in a century.

Not everyone heeded evacuation orders.

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As parts of Santa Rosa emptied out around him, Jas Sihota perched himself on his front porch with a garden hose, darting out every 15 minutes or so to douse nearby spot fires seeded by wind-blown embers.

The radiology technician said he had not slept in 24 hours.

“I wouldn’t have a house if I didn’t stay,” said Mr Sihota. At least 10 homes on his street beyond the reach of his hose were destroyed.

The Glass Fire marked the latest flashpoint in a historically destructive wildfire season throughout the western US.

In California alone, wildfires far have scorched 1.5 million hectares since January – far exceeding any single year in state history.

They have been stoked by intense, prolonged bouts of heat, high winds and other weather extremes that scientists point to as signs of climate change.

Since mid-August, fires in the state have killed 29 people and destroyed over 7000 structures.

-with AAP