Media playback is unsupported on your device Media caption It's the most lethal outbreak of wildfires in California's history

Forty people have died and hundreds are still missing in California after six days of wildfires that have devastated swathes of countryside and destroyed thousands of homes.

California's governor said it was "one of the greatest tragedies" the state had ever faced.

More than 10,000 firefighters are battling 16 remaining blazes.

Winds of up to 70 km/h (45mph) brought them to new towns, forcing many more people to evacuate.

One of the worst-affected areas is the city of Santa Rosa, in the Sonoma wine region, where 3,000 people were evacuated on Saturday.

"The devastation is just unbelievable," Governor Jerry Brown said on a visit to the city.

"It is a horror that no one could have imagined."

It is the most lethal outbreak of wildfires in the state's history. More than 100,000 people have been displaced. and whole neighbourhoods have been reduced to ash.

Firefighters had made some headway on Friday, clearing dry vegetation and other combustible fuel around populated areas on the fires' southern flank.

But the return of strong winds combined with high temperatures and dry air spread the fires further.

Media playback is unsupported on your device Media caption Officers braved the fires rampaging across the state's famous wine country

The huge fires have sent smoke and ash over San Francisco, about 50 miles away, and over some towns and cities even further south.

At least 13 Napa Valley wineries have been destroyed, a trade group said, and the owner of a winery in Santa Rosa told the BBC that the fires had destroyed millions of dollars worth of wine.