A wildfire in a rural area southeast of Los Angeles had forced the evacuation of thousands of people and burned more than 2,400 acres as of Tuesday evening, local officials said.
The Highland Fire began early Monday afternoon in Aguanga, a community in an unincorporated part of Riverside County, a vast area east of Los Angeles. Three structures had been destroyed and six others damaged as of Tuesday evening, the Riverside County Fire Department said in an update.
The department said the fire threatened more than 2,300 other structures and would likely take about a week to fully contain. It said the risk through Thursday evening was that easterly winds could continue to push the fire west and southwest, toward communities along California’s Pacific Coast.
The fire erupted in dry, bushy hills, and evacuation orders affected almost 4,000 people and 1,139 homes, said Jeff LaRusso, a spokesman for the fire department. The cause of the blaze was under investigation.
Another 500 homes were under evacuation warnings on Tuesday, Mr. LaRusso added, the step before an evacuation order, meaning that residents should consider leaving.
Residents posted videos and photos of strong winds and smoky conditions on social media, warning that the fire was moving fast. The winds and low humidity are the main factors driving the fire, Mr. LaRusso said.
The National Weather Service issued an air quality alert for the region through Thursday morning because of the wildfire smoke.
More than 1,100 emergency workers had responded to the blaze as of Tuesday evening, and the fire department said that firefighting aircraft were trying to suppress it from above.
Maggie Cline De La Rosa, a spokeswoman for the Riverside County Fire Department, said in an update on social media on Tuesday that those responding to the fire had adequate resources, including additional aircraft that were expected to arrive later.
“Please remain vigilant,” she said. “We have lots of firefighters on the ground doing their best to battle this fire.”
One firefighter was injured overnight, and he was taken to a hospital, where he was reported to be in stable condition, Ms. Cline De La Rosa said by email. No civilian injuries had been reported, she said.
The first firefighters to arrive on the scene encountered “a fire burning with a moderate rate of spread,” according to the fire department, and it has since intensified. The rapid spread of the fire was helped by the Santa Ana winds, which are dry, warm winds that come from the desert and are common during the cooler months of the year.
“These strong winds can cause major property damage,” the Weather Service said. “They also increase wildfire risk because of the dryness of the winds and the speed at which they can spread a flame across the landscape.”
Jesus Jiménez and Mike Ives contributed reporting.