More than 6,000 wildfires have hit the US state of California this year, burning an area of 580,100 hectares (1,435,263 acres) and causing damages worth more than $2.56bn, according to the California Department of Forestry and Fire Protection and the National Interagency Fire Center.

The Mendocino Complex fire, which was active for over 35 days, burned more than 186,000 hectares (459,000 acres), making it the largest complex fire in the state’s history.

Currently, the state’s focus is on two large wildfires in northern California.

The Delta fire, which broke out on Wednesday afternoon, tripled in size by Thursday morning, and by Thursday evening had spread over more than 8,900 hectares without being contained at all.

On Thursday afternoon, a TV station reporter tweeted that he had counted five homes destroyed in the fire. No injuries have been reported, but mandatory evacuations were ordered.

The Shasta County fire moved so fast that it prompted the closure of about 80km of the Interstate 5 highway in both directions. Seventeen tractor-trailers were abandoned on the highway and at least four of the vehicles were destroyed by the flames.

To the east of that is the Hirz fire, which is also burning parts of the Shasta National Forest, and is now 80 percent contained after burning more than 18,600 hectares.

Stanford Earth System Science Professor Noah Diffenbaugh stated that atmospheric conditions for California wildfires are expected to worsen in the future because of the effects of climate change on the state.

“What we’re seeing over the last few years is consistent with the historical trends in terms of increasing temperatures, dryness and increased wildfire risk,” he said.

Over the next few days, southeastern Idaho and northern Nevada will also be elevated to critical fire risk due to gusty winds and a drier air mass moving into the region.