The horrific fire also destroyed homes and caused power outages.
Some people have been running for their lives just ahead of the flames.
The blaze first ignited on Tuesday in a drought-ravaged mountain pass and a day later it had spread across nearly 47 square miles (12,200 hectares).
According to local official, more than 1,500 firefighters and other emergency workers were battling the Bluecut fire.
“It hit hard. It hit fast, with an intensity that we’ve never seen before,” San Bernardino County Fire Chief Mart Hartwig told reporters.
He warned that many families will return home “to nothing.”
San Bernardino National Forest spokesman John Miller described the conditions as “explosive.”
