Cal Fire's Daniel Berlant says the fire has been putting out a significant amount of smoke…and overnight, an inversion layer developed over the fire area.
"That's created the smoke to just kind of settle down into the valley area. So the homes in the southern portion of Placer County are waking up this morning to a significant amount of smoke. Not because the fire made runs last night and really put off a lot of smoke overnight. It's just because the smoke is all settling down in the valley."
Berlant says 1,368 people are working to fight the fire.
"As the state's fire department we were able to mobilize a lot of resources from across the area including Southern California and even some of the areas where we had fires earlier in the week like Colusa County. As those fires started to get contained we were able to move those resources back over here."
The evacuations are in effect for homes off Yankee Jims Canyon and the Shirttail Canyon area, as well as parts of Iowa Hill. The cause of the fire is still under investigation.