As the alleged arsonist is set to make his court appearance Friday, the unwieldy wildfire that officials say he deliberately sparked in Northern California is showing no signs of slowing down. The fire in the steep canyons of El Dorado County grew to more than 73,000 acres early Friday — nearly the size of Atlanta — and is only 10 percent contained since it started Saturday, according to the latest figures. “With the return of higher temperatures and lower humidity (Friday) or Saturday, the active fire behavior is expected to return,” officials warned as the blaze continues to burn through parts of Eldorado National Forest, threatening some 12,000 homes. As of late Thursday, no structures had been destroyed in the fire, which is costing $5 million a day to fight.

The suspected firebug, Wayne Allen Huntsman, 37, is charged with “willfully and maliciously” setting the blaze on federal land. Prosecutors say Huntsman has a criminal past, including convictions for possession of stolen property, grand theft and assault with a deadly weapon — but no motive for the wildfire has been given. Huntsman remains jailed on $10 million bail, and is expected to be arraigned Friday afternoon.

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— Erik Ortiz