The wildfires that have ravaged California's wine country this week are so widespread they can be seen from space.

Authorities fear the death toll will rise as around 23 separate blazes have engulfed more than 170,000 acres of land in the north of the state, killing 22 people and destroying around 3,500 homes and businesses.

In places the damage to the region's wineries has been so devastating that a boiling river of wine was spotted at the Paradise Ridge Winery in Santa Rosa, flowing beneath the smouldering ground where barrels have been incinerated.

Three days after the first fires were reported, the blazes continue to be fanned by the dry and powerful "Diablo winds" that stoke the infernos.

California governor Jerry Brown said 8,000 firefighters were battling to restore order with more resources arriving from neighbouring states.

Brown said: "We have had big fires in the past. This is one of the biggest, most serious, and it's not over."

"Now the winds are going back up and the humidity is going back down," said Heather Williams, a spokeswoman for Cal Fire, the state agency responsible for fire protection. "We're still not out of the woods. It's a very serious situation."

Loren Davis, of the state's mountain volunteer fire department, said simply: "It's a shitstorm."

Dry, windy weather is forecast for the next 24 hours, offering little in the way of respite. Gusts of up to 50 miles per hour and 10% humidity are expected throughout the rest of the week.