The Fred fire started Wednesday between Wrights Lake Road and Kyburz, and because of its proximity to U.S. 50, a main link between the San Francisco Bay area and South Lake Tahoe, the highway was shut down Wednesday evening.
Besides Kyburz and the nearby hamlet of Silver Fork which also was evacuated, there are about 150 cabins in the area, mainly along the South Fork of the American River.
By Thursday, the fire had increased to about 1,500 acres. There was no estimate on containment.
U.S. Forest Service spokeswoman Rita Yates said the cause of the blaze is under investigation, but a report from a fire manager indicated power lines had come down in the area.
To the south, firefighters are in their second week of fighting another wildfire that has burned more than 3,000 acres near Highway 88, another trans-Sierra highway.
That fire is located 17 miles east of Pioneer, between Bear River Reservoir and Salt Springs Reservoir.
``We don't have imminent structures threatened,'' Yates said. ``But we do have structure protections in place at Bear River Reservoir at the resort and 48 summer cabins there, which were mandatorily evacuated.''
The Power fire, named because of a nearby hydroelectric powerhouse, was 10 percent contained Wednesday night. Fire officials estimated that it would be fully contained Oct. 30.
