The so-called Holiday Fire has damaged or destroyed about 20 structures and is threatening hundreds more.
The blaze has burned between 50 and 80 acres and is 5 percent contained, Santa Barbara County Fire Department officials said Saturday morning.
The proclamation of a local emergency was made about 2 a.m. Saturday, which helps ensure that all county resources are available for the fire control efforts. It also helps facilitate potential state funding if needed.
More than 30 engines, including 120 firefighters, are on the scene battling the fire in 100-degree heat and gusty winds. Two night-flying helicopters assisted in the firefight overnight.
The wind-driven fire was first reported around 9 p.m. Friday in the 1500 block of Holiday Hill Road. The Santa Barbara County Sheriff's Department said a fire started at a home and then spread to nearby brush.
The blaze quickly spread and within 45 minutes threatened homes in the 1300 and 1400 blocks of Fairview Avenue, near Cathedral Oaks.
Nearly 2,500 people in the Cathedral Oaks neighborhood are evacuated.
Footage from the areas showed some homes up in flames as sundowner winds up to 45 mph and hot conditions fueled the fire.
An evacuation center is set up at the Goleta Valley Community Center, 5679 Hollister Ave. Anyone who needs help with animal evacuations is urged to call (805) 681-4332.
The cause of the fire is under investigation. No injuries have been reported.