Wildfires that have now been raging for six days in parts of California have killed at least 40 people and destroyed some 5,700 homes, officials say.

State fire services said 20 of the deaths occurred in Sonoma County, a wine-producing region. Most of the deceased — many of them elderly — are believed to have died shortly after the fires first broke out on October 8, having been taken by surprise as the blazes erupted in the middle of the night.

An estimated 10,000 firefighters are battling 16 large wildfires, most of them in the northern part of the state. Their task has been made more difficult by strong winds and high temperatures, with gusts of up to 64 kilometers per hour (40 miles per hour) reported on Saturday.

Read more: How climate change is increasing forest fires around the world  

'Unimaginable horror'

Californian governor Jerry Brown, who visited some burnt-out neighborhoods in the badly hit city of Santa Rosa, said on Saturday that the fires were one of the greatest tragedies his state had ever faced.

"It's a horror that no one could have imagined," he said after his visit. He has declared a state of emergency in several counties, including Sonoma, Mendocino, Lake and Napa.

'Gray destruction'

Williams Chalmers is one Santa Rosa resident who received a knock on his door from firemen in the pre-dawn hours of Friday morning telling him he had to leave his home immediately.

"We are safe," he said of himself and his wife, child and dog in a phone interview with DW. "We are running for our lives." Chalmers has had no news of his home since fleeing, but described a scene of total devastation in the area where he lives.

"It is a war zone. It is a moonscape of absolute gray destruction. The only thing standing from people's whole lives are chimneys," he said. "On the other hand, it is equal opportunity. It is laying waste to trailer homes, housing developments, mountaintop mansions, wineries, ranches, parks, schools. Needless to say, to people's lives."

Officials fear the death toll may rise as they search through thousands of damaged houses and vehicles.

Phone interview by Andy Valvur

tj, cb/jm (dpa, AP)