How did the Caldor Fire in California start?

The Caldor fire in east-central California ignited on 14 August four miles south of the community of Grizzly Flats in El Dorado County and has since grown extremely quickly, fanned by strong winds and high temperatures. The fire jumped Highway 50 at the weekend on the back of gusts of up to 40mph, forcing the partial closure of the road, after last week sweeping through Grizzly Flats, a town of 1,200 people, torching an elementary school, a post office and dozens of homes.

Tens of thousands of people have been evacuated as the fire advances, with evacuation orders likely to remain in place until the end of the month, according to local authorities. In its infancy the Caldor fire covered little more than 1,000 acres but in the space of a week it had grown to over 100,000 acres with the California Department of Forestry and Fire Protection (Cal Fire) reporting firefighters had managed to get a handle on the blaze with 5% containment as of Sunday night.

The blaze has seen 1,600 emergency service personnel mobilized so far, part of a wider deployment of some 13,000 firefighters in California tackling several active wildfires that have burned through over 1.5 million acres this summer.

The largest of these, the Dixie fire, now covers more than 725,000 acres according to Cal Fire. The Dixie fire is now the second-largest ever recorded in California, behind the August Complex blaze of 2020 that burned through 1.03 million acres.

Seven of 10 biggest California wildfires in last six years

Climate scientists have warned that continuing extremes of temperature and atmospheric conditions will lead to more severe fire seasons, coupled with longer summers and what many observers say is long-standing mismanagement of the state’s forests: 2018 was a record year for fires in California, with almost two million acres and in 2020 that number was more than doubled with 4.5 million acres scorched by wildfires. Seven of the 10 biggest wildfires in California history have occurred since 2015.

What caused the Caldor fire?

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The cause of the Caldor fire remains under investigation while the Dixie fire was potentially caused by faulty equipment belonging to the Pacific Gas and Electric Company. However, Cal Fire statistics state that some 95% of wildfires are caused by human activity including electrical failures, campfires, debris burning, smoking and arson.

NASA has also suggested that atmospheric phenomena could have contributed to the record-breaking 2020 fire season after 14,000 lightning strikes were recorded in the state in August alone. According to experts, around 5% of wildfires can be attributed annually to lightning.

The 2020 El Dorado wildfire was caused by a pyrotechnic used at a gender reveal party in San Bernardino, which eventually spread to over 20,000 and resulted in the death of a firefighter. Refugio Manuel Jiménez Jr and Angela Renee Jiménez were subsequently charged with various offenses including involuntary manslaughter and recklessly causing a fire. The couple, who have pleaded not guilty, face prison sentences of up to 20 years if found guilty of all the charges against them.