The Powerhouse Fire grew to 19,500 acres in northern Los Angeles County after a hot and windy Saturday, burning structures and prompting evacuations in rugged areas between the Santa Clarita and Antelope valleys.

At least five homes have burned in the blaze, said Los Angeles County Fire spokesman Keith Mora.

About 1,000 structures were threatened in the burn area, he said.

Three firefighters have been injured, and 960 firefighters, assisted by planes and helicopters, were expected to keep up the aerial and ground assault against flames on Saturday. The blaze was 20 percent contained, said John Wagner of the U.S. Forest Service.

The USFS told NBC News the fire had burned 19,500 acres as of 2:15 a.m. PT Sunday. That was up from 5,561 acres as of 1:40 a.m PT.

Temperatures reached the triple digits in some areas, including near the fire.

Also on Saturday, officials ordered evacuations for Elizabeth Lake Road and areas south of Lake Hughes, and upheld existing evacuations in the San Francisquito Canyon area.

Road closures were also ordered as far south as Castaic at Lake Hughes Road. 

The fire broke out Thursday near a hydroelectric plant known as Powerhouse No. 1 in San Francisquito Canyon, north of Santa Clarita.

Health officials urged people to avoid unnecessary outdoor activities as air quality in the Santa Clarita Valley and San Gabriel Mountains was expected to be unhealthy throughout the weekend due to the fire.

Evacuation orders were expected to remain in effect at least through Saturday night for the following areas: the Forest Service's Cottonwood Campground, L.A. County's Camp Mendenhall juvenile detention center and areas along Lake Hughes Road, Judy said. Other evacuations remained for areas north of South Portal Road and west of San Francisquito Canyon Road.

Power lines were reported threatened at one point Thursday, but there were no reports of service disruptions, Judy said.

One structure, described as an outbuilding, was destroyed in the blaze, Judy said.

The cause of the fire was under investigation.

A Red Cross evacuation center was set up at the Marie Kerr Park's recreation center at 2723-A Rancho Vista Boulevard in Palmdale. An evacuation center for large animals has been set up at the Antelope Valley Fairgrounds at 2551 West Avenue H in Lancaster

One person was killed and four others were injured when the car they were in was hit by an SUV being pursued by police in East Los Angeles, officials said.

The crash was reported after 2 p.m. Saturday in the 5300 block of Poplar Boulevard, said Katherine Main, a Los Angeles Fire Department spokeswoman.

Paramedics found one person dead at the scene.

Three men and a woman were taken to a hospital.

One man was in serious condition. The others were in fair condition, Main said.

Five people died in a fiery crash in the California community of Newport Beach in Orange County on Monday afternoon — four at the scene and one at a local hospital, NBC Los Angeles reported. The car split in half after striking the tree and caught fire, police said. Read the full story on NBC Los Angeles:

NBC Los Angeles: Fiery Car Crash Kills Five in Newport Beach

LOS ANGELES - A 63-year-old woman was fatally mauled by a pack of pit bulls while walking near her home in Southern California on Thursday and police were searching for the four dogs, law enforcement officials said.

A driver called police Thursday morning to report that four dogs were mauling the woman by the side of a road in a remote high desert area near Palmdale, California, Los Angeles County Sheriff's Captain Mike Parker said.

When a sheriff's deputy arrived on the scene a few minutes later, he found the woman being attacked by one dog, which circled and moved aggressively toward him as he approached, Parker said.

The deputy fired twice at the animal before it ran into the desert. There was no sign of the other three dogs, Parker said.

The victim, who was not immediately identified, died in an ambulance while being taken to a hospital, said Los Angeles County Care and Control spokeswoman Evelina Villa.

Authorities were searching for the tan-colored dogs and issued warnings to residents of Palmdale, about 65 miles east of Los Angeles.

"Sheriffs deputies are knocking on doors in the neighborhood, patrolling and warning people in the area, but we have not picked up any leads since the deputy fired the shots," Parker said.

Homicide detectives were on the scene and Parker said the dog's owners could face charges.

Members of the woman's family had told police that she walked daily in her neighborhood, he said.

Record-setting temperatures, erratic winds and a parched landscape spell a dangerous fire season for California, experts said on Friday as firefighters fought to control several large blazes of a kind that usually would not raise thick plumes of smoke over the horizon until late fall.

“This is definitely a preview of a long, hot, incendiary summer,” said William Patzert, a climatologist at the Jet Propulsion Laboratory in La Cañada-Flintridge.

A combination of early, powerful gusts from the inland to the coast, called Santa Ana winds, breathed life into the roaring orange flames that devoured brush and raced down hillsides near Malibu toward the Pacific Ocean on Thursday night. The sea-bound winds pour into the southern part of the state from the northeast and southwest, becoming drier and hotter as they approach the coast, said Stuart Seto, a weather specialist at the National Weather Service in Oxnard, Calif.

This week, “all the ingredients” came together across parts of California, Patzert said.

The Spring Fire in Ventura County was 56 percent contained, Cal Fire said on its Twitter feed Saturday evening, after jumping to 28,000 acres on Friday, shutting down a portion of the Pacific Coast Highway for a time and drawing nearly 1,900 fire personnel, eight helicopters, and a half-dozen air tankers. The fire damaged at least 15 residences and dozens of other structures, NBCLosAngeles reported, citing fire officials.

The Summit Fire in Riverside County was fully contained at about 3,166 acres, Cal Fire said. Riverside County fire officials said two firefighters were injured as they worked to draw a line around the flames, which destroyed one home, NBCLosAngeles.com reported.

More than 1,000 firefighters battled a third blaze, the 6,720-acre Panther Fire, in Tehama County.

“At this point it’s just a question of meteorology, of the Santa Anas, and of course in Southern California 95 percent of the fires are human (caused),” Patzert said. “Fire is fuel plus meteorology plus ignition.”

Many California residents in areas prone to wildfires have known the fear of watching flames lick the borders of their property, but in the past wide-scale destructive fires usually have not struck until summer or fall. A series of 22 major fires across seven Southern California counties destroyed more than 2,200 homes in 2007 – but those fires lasted over three weeks from October to November, according to a report by the Orange County Fire Authority.

The 2009 Station Fire burned over 160,000 acres, destroyed 80 structures, and killed two county firefighters. That fire, the largest in Los Angeles County history, wasn't sparked until late August, according to an after action review. The cost to fully contain the Station Fire topped $95 million, the U.S. Fire Service reported.

“This is certainly one of the earliest fire seasons I remember,” Patzert said.

Jonathan Alcorn / Reuters

Firefighters battle the Springs Fire at Point Mugu State Park on May 3. A wind-driven wildfire raged along the California coast north of Los Angeles early on Friday.

Firefighters around Camarillo contended with unpredictable Santa Ana winds as flames threatened residences on Thursday and Friday. Such winds drive from inland to the sea, but they usually occur during the fall and winter months.

“We’re having Santa Ana events in May,” Capt. Mike Lindberry of the Ventura County Fire Department said on Thursday. “An event like this … it hasn’t happened in my career.”

Those winds make it harder for firefighters to corral the flames as they leap across scrubby, uninhabited areas.

“The winds are just super strong. They couldn’t get ahead of the fire because the winds are so strong, and the heat was tremendous,” said Seto.

Extremely dry conditions for this time of year have also contributed to the growth of the fires, Seto said. The dryness of the vegetation that fueled the flames in the Camarillo area was comparable to what is usually measured in July, he said.

Temperatures hit a record high for the date of 98 degrees in Camarillo on Thursday, Seto said, topping the previous high of 94 degrees in 2004. Normal for this time of May is about 74 degrees, he said.

While parts of the Plains states and upper Midwest saw late-season snowfall earlier this week, officials in California have said that the state's snowpack is lighter than normal. That means the amount of water that flows into state reservoirs over coming months will be less than usual as the snow melts.

“I’m finding nothing,” Frank Gehrke, chief surveyor for the Department of Water Resources, told The Associated Press on Thursday. “Seriously, there is no snow on the course at all.” The water content in California’s high-altitude snow turned out to be only 17 percent of what it usually is, the department reported.

Fire officials have been warning about the dangerous fire conditions in California for several months. After an 100-acre brush fire flared up in Monrovia in April, city fire Chief Chris Donovan told reporters that experts anticipated a “very dry – and very bad” season.

A wildfire outlook produced by the National Interagency Fire Center in Boise, Idaho, predicted “above normal” fire potential for Southern California, the Sacramento Valley and parts of southern Oregon in May. The likelihood of significant fires will expand through Washington, Arizona, New Mexico and other large swaths of California over the summer months, according to the fire center’s outlook.

“This big picture is across the country it’s been sort of two winters, as the Northeast and the Midwest had a never-ending winter with spring that just didn’t want to show up,” Patzert said. Meanwhile, in Southern California, “the rain spigot essentially just turned off in January.”

“It’s a no-brainer to tell you that it is going to be a busy fire season,” he said.

Slideshow: California wildfires

Jonathan Alcorn / Reuters

A fire engine is parked on Pacific Coast Highway as the Springs Fire burns in the hills at Point Mugu State Park on May 3.

Launch slideshow

Related:

• 'Monster' California wildfire reaches ocean, pushes toward Malibu
• 12-square-mile Springs Fire spreads toward Ventura County Coast
• Thousands in Calif. wildfire's path evacuated

Slideshow: California wildfires

Jonathan Alcorn / Reuters

A fire engine is parked on Pacific Coast Highway as the Springs Fire burns in the hills at Point Mugu State Park on May 3.

Launch slideshow

Southern California firefighters battled back a series of sprawling, brush-fueled wildfires on Friday, including one that had blazed a trail to the beach in Ventura County overnight and was pushing toward the upscale city of Malibu, officials said.

At least six fires of various sizes flared up as high temperatures, low humidity and brittle brush left the state a veritable tinderbox over the last two days, although conditions were improving by the afternoon.

The so-called Springs Fire, made worse by howling Santa Ana winds and unusually dry vegetation, crept within "seven or eight miles" of Malibu around 2 a.m. local time [5 a.m. ET], Ventura County Fire Department spokesman Bill Nash said.

"We've got hot, dirty, unglamorous firefighting work going on right now, guys with shovels trying to scratch out lines on the ground," Nash said in the early hours of Friday. "We've got those guys on these steep hillsides in the dark with nothing but the light of the fire and a flashlight."

Dry winds from inland to the ocean brought gusts of 40 to 50 miles per hour to the Southern California region on Friday. By 1 p.m Pacific time, the temperatures had dropped 11 degrees and the humidity shot up to 19 percent. Warnings remained in effect as winds stoked the flames, the National Weather Service reported.

“We’re looking good,” Battalion Chief Fred Burris of the Ventura County Fire Department said on Friday, according to NBC Los Angeles. “We believe we’re past the major structure threat at this time.”

The Springs Fire grew to 10,000 acres and was 10 percent contained as of early Friday morning, according to the California Department of Forestry and Fire Prevention.

An eight-mile stretch of the Pacific Coast Highway was shut down for a time on Thursday night as bright orange flames raced down scrubby hillsides toward the Pacific Ocean.

“We are asking members of the public to be very aware: This is very dangerous,” said Ventura County Fire Department spokesman Tom Kruschke. “This is still a moving fire. If you were asked to evacuate, it will be a while before you are allowed in. And if at one point you are uncomfortable, please leave the area. It’s not safe to stay.”

“The firemen have been doing a really great job of keeping it away from the houses,” said Sara Mallam, a resident of Newbury Park, near Thousand Oaks, Calif. “It is kind of scary to see it get so close, but they really seem to know what they’re doing.”

Though the more than 925 firefighters on the scene got a brief overnight reprieve as the humidity jumped and winds died down, winds picked up again after sunrise on Friday.

Firefighters received help from tankers and helicopters in the air after the sun rose on Friday, according to a release from the Ventura County Fire Department.

Complicating the situation is the extremely dry plant life left from a season in which only about five inches of rain fell, officials said.

Friday "may be the hottest day of the week, and the humidity we do expect to plummet," Nash said. "We’re faced with a situation right now where the vegetation on the hillsides, the moisture level is what we typically see in August."

The cause of the fire remained under investigation Friday. There had been no lightning or other natural fire-starting phenomenon in the area when the blaze began, Nash said.

In Riverside County, hundreds of firefighters had begun to gain control of a wind-lashed 3,000-acre wildfire that consumed one home and led to the evacuation of hundreds of others.

The Riverside County fire, dubbed the Summit Fire, remained at just under 3,000 acres Friday morning and was about 65 percent contained, according to a Cal Fire incident report. Firefighters worked to improve containment lines around the raging blaze that threatened homes on Wednesday, but one building had been destroyed.

Two of the 650 firefighters trying to tame the blaze sustained non-life-threatening injuries, according to the report.

Additionally, more than 1,000 firefighters were battling a third major wildfire, designated the Panther Fire, Friday in rugged timberland in Northern California’s Tehama County about 30 miles east of Chico.

NBC News' Jeff Black contributed to this report.

Related:

• Thousands in Calif. wildfire's path evacuated
• 'Monster' California wildfire reaches ocean, pushes toward Malibu
• 12-square-mile Springs Fire spreads toward Ventura County coast

This story was originally published on Thu May 2, 2013 9:46 AM EDT