The 25-acre Lookout Fire at the edge of the Los Padres National Forest in Santa Barbara is 10 percent contained and still threatening dozens of structures.
"Approximately 40 structures have been evacuated with another 60 structures at risk. A shelter has been opened on North Turnpike and large animals are being accepted at Earl Warren Showgrounds," according to an alert from the Santa Barbara County Office of Emergency Management.
The Red Cross shelter was set up at Wake Center SBCC, located at 300 N. Turnpike Road (map), and the showgrounds are located at 3400 Calle Real (map).
Eight air tankers, five helicopter and about 300 firefighters are battling the blaze, said Andrew Madsen of the US Forest Service.
"We've got about 50 percent of the perimeter coated with the retardant, so that's going to assist our hand crews as they begin to cut containment line," Madsen said. "The up-slope spread has been stopped so we're working on the flanks right now."
Madsen estimated the fire had consumed between 20 and 25 acres.
At least one firefighter suffered a minor leg injury and the cause of the fire remains unclear, he said.
Some power lines in the area were downed. About 100 residents were affected, but Southern California Edison expected most power to be restored Wednesday afternoon, according to the utility's website.
Earlier, Santa Barbara County Sheriff's deputies went door to door warning residents. Authorities also made reverse 911 calls to alert the community about the fire danger.
Evacuation map at NBCLosAngeles.com: Lookout Fire
Animal rescue teams were also working to save horses and other large animals in the area, said Sgt. Mark Williams.
Although buildings are being threatened no structural damage has been reported yet.
"It's a rural setting above Santa Barbara. You have a lot of homes that are just scattered around up there," Madsen said. "We're coming at it with everything that's at our disposal."
Also at NBCLosAngeles.com: Unseasonable heat wave grips Southern California
Wind speeds were expected to range between 5 and 10 mph with no real gusts throughout the afternoon. Humidity will range between 20 to 40 percent, and temperatures are expected to drop over the next few days.
The forecast is calling for much better firefighting conditions starting Thursday: on-shore flow was expected to increase moisture in the air, dampening flames.
"There are some weather forecasts for increasing winds this evening, whether they're sundowners or off-shore stuff. That's why the response is critical at this early stage so we can knock this down before the winds arrive later today," Madsen said.
The fire began about 8 a.m. at Highway 154 and Painted Cave Road (map), according to the Santa Barbara County Office of Emergency Management. The area in the San Marcos Pass is about 12 miles north of Santa Barbara and 20 miles southeast of the Lake Cachuma Recreation Area.
The vast Los Padres National Forest has seen multiple large fires in recent years. In 2007, the Zaca Fire destroyed more than 240,000 acres -- the second-largest blaze in state history.
In June 1990, the area burned during what became known as the Painted Cave Fire. Fueled by hot, dry winds, the fire quickly burned out of the rugged hillside area and raced through residential areas.
More than 400 homes were destroyed.
"The difference there was that the Painted Cave fire of 1990, that occurred in July and that was a malicious fire-start dispute between some neighbors up there. The sundowner winds were in full effect. That fire kicked off in the evening time and it basically rolled all the way down the hill to the 101. We don't have the winds here. It's later in the season, but it's just as warm," Madsen said.
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