Shocking photos have shown parts of California plunged into darkness as wildfires spread across the state.
One blaze in southern California has burned through 6918 hectares and forced residents from their homes, after a firework at a gender reveal party sparked the devastating blaze.
In Northern California the Creek Fire has burned through 45,500 acres and led to 200 people having to be rescued by the military on the weekend.
The group became trapped at the Mammoth Pool Reservoir northeast of Fresno when fast moving wildfires trapped them.
Another rapidly-spreading fire near San Diego, the Valley Fire, has so far burned 10,000 acres and destroyed 11 structures, Cal Fire said.
Record temperatures over the three-day Labor Day weekend have aggravated already dangerous fire conditions and further stressed exhausted California firefighters.
Temperatures reaching more than 43 degrees Celsius were forecast for the Los Angeles area on Monday.
More than 500 firefighters and four helicopters were battling the El Dorado blaze east of San Bernardino, which started Saturday morning, California Department of Forestry and Fire Protection (Cal Fire) said.
Residents of several communities in the area have been ordered to evacuate. “CAL FIRE Law Enforcement has determined the El Dorado Fire, burning near Oak Glen in San Bernardino County, was caused by a smoke generating pyrotechnic device, used during a gender reveal party,” Cal Fire said on Twitter.
“Those responsible for starting fires due to negligence or illegal activity can be held financially and criminally responsible,” it warned.
Gender reveal parties are held during pregnancy to unveil the sex of the expected child, sometimes announced by pink or blue smoke fireworks.
With hot and dry conditions, California is suffering through a particularly busy fire season this year, with more than 1.6 million acres destroyed so far, including in three of the biggest blazes in the state’s history.