Driven by fierce Santa Ana winds, four intense fires near Los Angeles grew to engulf more than 115,000 acres Thursday, and officials say residents should be prepared for dangerous fire conditions, as both strong winds and very dry conditions persist through Friday.

More than 4,500 firefighters have been working to control the fires. But the largest blaze, the Thomas Fire, has exploded to 96,000 acres since it was started earlier this week. Containment of that fire is now at five percent.

On Thursday morning, the intense heat of the Thomas fire was seen generating a pyrocumulus or flammagenitus cloud — the towering mushroom clouds that sometimes result from volcanic eruptions and other extreme activities.

Forecasters had predicted wind gusts of up to 80 mph, saying that this week would bring the worst of the seasonal Santa Ana winds. The California Department of Forestry and Fire Protection had issued a dire "purple" warning last night, referring to the only color above red on the wind scale. But that forecast has since been downgraded to a red alert.

Santa Ana wind speeds were expected to peak by midday Thursday,the San Diego office of the National Weather Service said, citing a peak gust of 88 mph at Sill Hill this morning. Many other areas reported gusts in the 60-mph range. The agency says that while the highest speeds will be seen today, strong winds will resurface in a wide region where humidity levels were below 5 percent on Thursday — dangerous conditions that could cause a fast-moving and intense blaze to wreak havoc. As they try to control existing fires, firefighters have also been able to snuff out several threats.

"New and smaller fires erupted this morning. A three-acre vegetation fire was quickly extinguished in Riverside County before it was able to spread to nearby businesses," Alex Cohen reports from member station KPCC. "In the city of Anaheim, another blaze damaged four units at a commercial building."

Cohen adds, "Roughly 200 firefighters were sent to the scene of a fire along the coast in Malibu - it was contained in an hour."

An end to the threat is still a long way away. The National Weather Service office in Los Angeles and Oxnard says it expects critical fire weather conditions to linger into Saturday.

As The Associated Press notes, "The wilder winds could easily make new fires explode too, as one did Wednesday in Los Angeles' exclusive Bel-Air section, where a fire consumed multimillion-dollar houses that give the rich and famous sweeping views of Los Angeles."

The fires have produced vivid and shocking images of massive walls of flame. But on Wednesday night, a much smaller scene of peril played out, when a man was seen getting out of his car to rescue a rabbit that was near perilous flames on Highway 1 in La Conchita. In a dramatic sequence captured by RMG News, the rabbit ran away from the man — and toward the flames — before he managed to corral it. He declined to be interviewed afterwards.

Thousands of people have been placed under evacuation orders. And making the situation more dangerous for anyone trying to flee affected areas, the fires have forced closures on arterial roads. In addition to the brief shutdown of a stretch of the 101 on Thursday, a portion of the 405 freeway was closed in both directions for a time on Wednesday.

Mary Plummer, a reporter with member station KPCC in Pasadena, tells Morning Edition that "these fires are affecting a real range of geographic areas — some very urban, some very rural. So, it's a real logistical problem."

Cal Fire estimates that hundreds of structures, including 200 homes, have been destroyed, and that as many as 200,000 people are under evacuation orders. Some 12,000 structures are considered in danger.

Gov. Jerry Brown declared a state of emergency for Los Angeles and Ventura counties, which will free up state resources.

Smoke and dust from the fires have also raised health concerns.

"Air quality reached 'hazardous' levels in Santa Barbara Thursday,' KPCC reports, citing the Santa Barbara County Air Pollution Control District. "An air monitoring station in Goleta recorded 'very unhealthy' levels, and in Lompoc, conditions were 'unhealthy.'"

San Luis Obispo County says it was also being affected by the smoke, cautioning residents to reduce their exposure to smoke and ash.

Remarkably, so far no deaths have been reported as a direct result of the fires. But many people have been evacuated, and many have already lost homes and other property.

Patricia Hampton, a homeless woman who lost her tent, found shelter at the Ventura County Fairgrounds, which is serving as an evacuation center.

"It was surreal," she tells member station KPCC. "The entire town was pitch black. I looked to the left and the hillside was on fire; I looked to my right and it was just coming over the ridge, huge flames."

Member station KCLU says that firefighters have made progress, raising containment of the Thomas Fire, the largest of several, from zero to 5 percent. As of Thursday morning, the fire had grown to 96,000 acres.

Ventura County Fire Captain Tony McHale said it was still a long way from under control.

"There's enough fire around; there's dry fuel; the humidity is still low. We're still very much in danger. So we can't let our guard down at all," McHale said.

The Thomas Fire has burned a 10-mile path from Santa Paula to the Pacific Ocean, jumping U.S. Highway 101 along the way.

The Los Angeles Times reports that "As flames raged toward neighborhoods in Ojai, Carpenteria and Fillmore late Wednesday, officials issued new evacuation orders in Ojai Valley, notifying residents with an emergency cellphone alert. Authorities said they were helping residents of five assisted-living facilities evacuate, while people at Ojai Hospital were advised to shelter in place."

Southern California Public Radio (SCPR) adds: "Areas northeast of Ojai have seen the most fire growth since Wednesday morning, officials told reporters. Authorities say they are conducting damage assessments in the area to determine how many homes have been damaged."

In Los Angeles County, the Creek Fire, affecting 12,605 acres, is 10 percent contained and the Rye Fire, of 7,000 acres, is 15 percent contained. The much smaller Skirball Fire was considered 20 percent contained and has prompted the evacuation of about 700 homes, one apartment building and an elementary school, according to SCPR.

Many school districts in the area have shut down for the rest of this week. The Bel-Air fire prompted UCLA to cancel classes after noon on Wednesday; all classes are also canceled for Thursday, the Daily Bruin reports.

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