The conflagration, which had blackened 17,364 acres along California's scenic central coast as of Saturday afternoon, was being fed by brush and vegetation that had not burned since 1955, according to fire officials.
Officials said that overnight Friday into Saturday, the fire grew significantly on the southwestern flank, pushed by Sundowner winds.
"We had a very calm night as far as the fire behavior goes and that's because the wind never really picked up", he said.
Fire and sheriff's officials concerned about the weather's impact on the blaze issued evacuation orders Friday evening for additional areas near Paradise Canyon Road from Highway 154.
The forecast is expected to continue to spur the fire's growth in the coming 24 hours, with wind gusts of up to 35 mph, temperatures in the mid-90s and low humidity. Those orders remained in place Saturday.More news: Qatari FM says Gulf standoff can not be resolved in a day
Closure of the fire area is meant to help ensure that members of the public are not injured within the fire perimeter, to keep the area clear for fire equipment traffic, and to allow for the scorched landscape to begin the rehabilitation and regrowth process.
Almost 3,000 people who were forced to flee their homes near Cachuma Lake and the community of Goleta remained under evacuation orders as fire officials said another evening of Sundowners could drive the flames toward populated areas. Currently, 1,615 fire personnel are battling the blaze. But fire crews are prepared if that should happen, officials said. The cause of the fire remains unknown.
Meanwhile, the 28,687-acre Alamo fire near Santa Maria was 93 percent contained as of Saturday morning, according to the California Department of Forestry and Fire Protection.
In a statement, the sheriff's office and other emergency services responders spoke about their work to evacuate the Circle V Ranch Camp and the 88 campers and 26 staff and counsellors in residence.