Officials say crews fighting the Trailhead Fire in Placer and El Dorado counties made good progress Thursday but that the fire became more active. As of Friday afternoon, the blaze has charred 2,551 acres.
The wildfire is burning through hard-to-access terrain in steep canyons along the middle fork of the American River.
CAL FIRE says at least 400 homes have been evacuated. The fire is threatening some than 2,600 homes, businesses and other structures.
No damage or injuries had been reported so far. Containment is at 12 percent.
The Red Cross has set up an evacuation center in Auburn.
A community meeting will take place Friday night at the Foresthill High School at 7 p.m. Fire staff will provide an update on the fire and will answer questions from the public.