Firefighters are battling a wind-driven brush fire in the exclusive Hollister Ranch community in Santa Barbara County.The Hollister fire started around 11:30 a.m. Saturday near Hollister Ranch and Del Norte roads, authorities said. As of 2:45 p.m., it had grown to an estimated 75 acres, and one structure was threatened, said Sam Ferguson of the Santa Barbara County Fire Department. Some residents were reportedly told to evacuate as a precaution. No containment was reported.The cause of the fire is under investigation, but initial unconfirmed reports indicated that a suspect was taken into custody. An ambulance unit was called, and an investigator was responding to the scene, Ferguson said.The fire, which authorities estimate has the potential to grow to 500 to 1,000 acres, was burning through dense front-country chaparral, driven by erratic winds, Ferguson said. Steep terrain was also complicating the fight as the flames reached a drainage with heavy brush that was accelerating the spread, he said.“Hollister Ranch is a series of canyons, and specifically it had dropped into one particularly vegetative area that had caught, and that was contributing to the spread,” Ferguson said.The 14,500-acre Hollister Ranch is a gated subdivision along the Gaviota Coast, famed for its untouched beaches, which have been the subject of legal battles over public access.One silver lining was that vegetation in the area remains relatively moist due to rains earlier in the season, with the latest measure of fuel moistures in the West Gaviota area over 100%, Ferguson said.“The fuel moistures up there are still pretty optimal as far as preventing spread, but the wind and amount of brush, those are the main things affecting it right now,” he said.There were 10 engines assigned to the fire, with an additional five on the way, as well as two water tenders, a dozer, two helicopters and four fixed-wing aircraft, Ferguson said.California’s winter weather has spurred concerns that its wildfire season — which authorities say is a misnomer as large, climate change-supercharged fires now start year-round — will arrive early and burn intensely. January and February were the driest first two months of the year on record across much of California. February was also unusually warm, and in much of Southern California, repeated Santa Ana wind events dried out vegetation after an uncommonly wet December.Crews have already battled several unseasonably early wildfires this year, including the 553-acre Jim fire and the smaller San Juan fire in the Cleveland National Forest, the 154-acre Emerald fire near Laguna Beach, and the Sycamore fire near Whittier, which burned only 7 acres but destroyed two homes.Times staff writers Paul Duginski and Hayley Smith contributed to this report.