The number of people killed by a massive blaze in northern California rose to 42 on Monday, making it the deadliest wildfire in the history of the state.Thousands of firefighters spent a fifth day digging battle lines to contain the "Camp Fire" in the foothills of the Sierra Nevada mountains north of Sacramento, while search teams were on a grim mission to recover the dead."As of today, an additional 13 human remains have been recovered, which brings the total number to 42," Sheriff Kory Honea told a news conference.The blaze is "the deadliest wildland fire in California history," Honea said.Although it is difficult to be certain due to inconsistencies in record keeping and categorisation, the Camp Fire appears to be the deadliest American wildfire in a century – since the Cloquet Fire killed an estimated 1 000 people in Minnesota in 1918.The Camp Fire is the largest of several infernos that have sent a quarter of a million people fleeing their homes across the tinder-dry state, with winds of up to 100km/h fanning the fast-moving flames.In addition to the historic loss of life, the Camp Fire blaze is also more destructive than any other on record, having razed 6 500 homes in the town of Paradise, effectively wiping it off the map.More than 5 100 firefighters from as far as the states of Washington and Texas have been working to halt the advance of the inferno as "mass casualty" search teams backed by anthropologists and a DNA lab pick through the charred ruins to identify remains – sometimes reduced to no more than shards of bone.At least 44 people have died in fire zones in north and south California, where acrid smoke has blanketed the sky for miles, the sun barely visible.'Major disaster' declaredUS President Donald Trump "declared that a major disaster exists in the state of California and ordered federal aid to supplement state, tribal, and local recovery efforts in the areas affected by wildfires," the White House said in a statement.The move makes aid available to the state's fire-hit Butte, Los Angeles and Ventura counties.On the ground, cars caught in the flames have been reduced to scorched metal skeletons, while piles of debris smoulder where houses once stood, an occasional brick wall or chimney remaining.Glenn Simmons, 64, told AFP in the nearby town of Chico that he had been sleeping in his car since Thursday, unable to find a space in a shelter."I was planning on maybe moving out of state, or into southern California... Everything is burned up. I have my clothes and I have a backpack, and that's pretty much it," he said.The Camp Fire has reduced around 45 square kilometres of Butte County's forested hills mostly to charred wasteland – an area which hasn't seen rainfall of more than one centimetre in more than 30 weeks.It is currently 25% contained, the California Department of Forestry and Fire Protection (Cal Fire) said.Three firefighters have been injured in the effort to quell the blaze's advance.At the southern end of the state, another three firefighters have been injured battling the Woolsey Fire, which has devoured mansions and mobile homes alike in the coastal celebrity resort of Malibu.The blaze is similar in size to the Camp Fire but has been much less destructive, and the death toll has been limited to two victims found in a vehicle on a private driveway.'The new abnormal'While some Malibu-area residents were allowed to return home late on Sunday, the city of Calabasas, just northeast of coastal Malibu, came under evacuation orders."This is not the new normal, this is the new abnormal. And this new abnormal will continue, certainly in the next 10 to 15 to 20 years," California Governor Jerry Brown said on Sunday in a stark warning over the likely damaging effects of climate change."Unfortunately, the best science is telling us that the dryness, warmth, drought, all those things, they're going to intensify."Over the weekend, the Woolsey Fire engulfed parts of Thousand Oaks, where the community is still shell-shocked after a Marine Corps veteran shot dead 12 people in a country music bar on Wednesday.The blaze has consumed around 37 600 hectares, destroyed an estimated 370 structures and was 30% contained, according to Cal Fire.Offering helpSinger Miley Cyrus' home was one of the buildings destroyed in southern California."Completely devestated (sic) by the fires affecting my community. I am one of the lucky ones. My animals and LOVE OF MY LIFE made it out safely & that's all that matters right now," she tweeted."My house no longer stands but the memories shared with family & friends stand strong."Many of the affected area's residents own horses, and Twitter has been flooded with messages from people seeking and offering help.Actor James Woods, a rare political conservative in liberal Hollywood, has made new friends by using his Twitter account to help find missing people and getting help for pets, including horses.The Ventura County Humane Society said it was "deeply humbled" by a $100 000 donation from actress Sandra Bullock and her family to rescue and care for animals evacuated from the fires.