The 15,400-acre fire, burning 20 miles northwest of Santa Barbara in Refugio Canyon, was 5% contained as of Wednesday evening.
The fire grew quickly after sparking on Monday, officials said. The cause is unknown.
At least 1,300 personnel are responding to the blaze, with more expected to join the effort.
“Hoping for favorable winds for fixed-wing aircraft to engage,” Santa Barbara County Fire tweeted Wenesday.
Meanwhile, 20 California counties have been warned by utility company PG&E that they could see a Public Safety Power Shutoff (PSPS) Thursday in response to weather conditions that could fuel yet another wildfire.
The counties under the alert are: Butte, Colusa, Contra Costa, Glenn, Humboldt, Kern, Lake, Napa, Plumas, San Luis Obispo, Santa Barbara, Shasta, Sierra, Solano, Sonoma, Stanislaus, Tehama, Trinity, Yolo and Yuba.
Thousands under air quality watch
The Santa Barbara Public Health Department and air pollution control officials issued an Air Quality Watch on Tuesday due to smoke from the Alisal Fire.
“This is a dynamic situation, and local air quality conditions can change quickly.”
Smoke from the fire can be seen throughout the southern part of the county, including the Santa Ynez Valley and along the Gaviota coastline, fire officials said on InciWeb.
In particular, people with heart or lung conditions, older adults, pregnant people and children should not spend too much time outside and limit outdoor exercise to avoid inhaling the smoke and particles in the air, health officials said.