Five people have died, two are still missing and tens of thousands more are at risk of losing their homes as dozens of wildfires rip through Northern California.
A further 33 civilians and firefighters have been injured during across several counties in the state, as fire services have struggled to contain more than 20 separate blazes sparked by lightning strikes during a heatwave.
Among those who have died are a helicopter pilot who crashed while trying to drop water on one conflagration in central California and a utility worker from Pacific Gas & Electric.
The worst fires are around the Bay Area and San Francisco in the north of the state, where 1,250 sq km of forest and brushland have been burned to a crisp.
Some 10,000 firefighters have been deployed to battle the flames, stretching California’s capacity to the limit. Some are working 72 hour shifts on the frontlines, three times the normal 24 hours, but still fire chiefs have said they do not have enough resources.
State officials have requested help from neighbouring fire departments in other states, saying they need at least 375 fire engines and crews to bolster their own resources.
“That’s going to allow our firefighters that have been on the front line since this weekend to have an opportunity to take some rest,” said Daniel Berlant from California’s Department of Forestry and Fire Protection.
But help may be some time in arriving. US Forest Service firefighters are tied up battling blazes on federal land, while the unprecedented demand means assistance will have to travel from further afield than normal.
Cal Fire’s assistant chief Billy See said his crews badly needed reinforcing. “We’re still drastically short for a fire of this size,” he told a press conference about a complex of fires in Santa Cruz and San Mateo counties, south of San Francisco.
“Today we saw a growth of approximately 700 to 1,000 acres an hour in heavy timber. That’s a dangerous rate of spread for our firefighters and for all those residents out there.”
Mr Berlant said 175 buildings had already been consumed by the wildfires and 50,000 more homes were threatened.
Firefighters have pleaded with Californians to be ready to evacuate at a moment’s notice, as delays in moving when told to put crews’ lives at risk as they have to stay behind.
Cal Fire has also urged locals not to try to put out fires themselves, following reports of volunteer firefighting brigades organising on social media.
“The dangers out there to their own lives outweigh anything they can accomplish,” a spokesman for the fire service said. “They’re putting their lives in jeopardy.”
In the mountainous costal region south of San Francisco, 48,000 people have already been told to evacuate their homes as a complex of fires approached. The blazes have already scorched 194 sq km and were now threatening 21,000 structures if they could not be stopped.
Several other smaller fires across the state have required local evacuation orders, with tens of thousands of residents either told to flee or warned to be ready to evacuate in the coming days.
As well as lives and property at stake, the wildfires have also caused serious damage to some of California’s world-famous state parks, including the Big Basin Redwoods, outside Santa Cruz.
The crop of ancient redwood trees has been protected since 1902 – making it the oldest such park in California – but a conflagration has burned the park’s headquarters and other facilities.
“We are devastated to report that Big Basin, as we have known it, loved it, and cherished it for generations, is gone,” said the Sempervirens Fund, an advocacy group for the trees, in a statement.
“Early reports are that the wildfire has consumed much of the park’s historic facilities. We do not yet know the fate of the park’s grandest old trees.”