Story highlights New blaze on Camp Pendleton becomes sixth wildfire burning Friday evening

Charge of arson is filed against one man for a small fire in Oceanside

176,000 evacuation notices have been issued countywide

A 19-year-old man and a 17-year-old juvenile, both of Escondido, are arrested in fire probe

Firefighters in San Diego County continued their four-day assault Friday evening against several wildfires that so far have scorched more than 31 square miles.

Meanwhile, investigators filed an arson charge in one small fire in the county.

San Diego County District Attorney Bonnie Dumanis announced Friday the first arson charge in the spate of fires. A man was charged in connection with a small fire in the San Luis Rey riverbed area in Oceanside, she said.

At a press conference, the prosecutor identified the man charged as Alberto Serrato, who's accused of adding brush onto an existing fire, Dumanis said.

"Citizens were there and observed this," and two citizens notified police, who then made an arrest, she said.

The arson charge against Serrato carries a sentence of up to seven years in prison upon conviction, Dumanis said.

Neither Serrato nor his attorney were immediately available for comment.

Meanwhile, the prosecutor is weighing whether to press charges against a 19-year-old man and 17-year-old juvenile, both of Escondido, who were arrested Thursday in connection with a small fire that was extinguished, Dumanis said.

No countywide estimates of damage to houses, apartments and businesses were available Friday, county officials said.

The fires were extraordinary for their number so early in the year and for how close they came to residential and business areas, even torching several structures. Thousands of firefighters used air tankers, specially equipped DC-10s and military helicopter to douse the flames this week.

A more-than-3,000-acre fire in San Marcos was all but out of control with only 10% containment Friday, authorities said.

When Elisha Exon saw towers of smoke looming over her San Marcos, California, home, she knew it was time to go. The only problem: All the nearby places she'd normally take her family in an emergency were threatened by fire, too.

"You kind of feel like your only safety would be to hop town, completely," she told CNN's "New Day."

The stunning explosion of fires this week in San Diego County -- six were still burning Friday evening -- stirred suspicions of arson and sent thousands of people fleeing from their homes beginning Tuesday.

Meanwhile, Camp Pendleton reported the latest wildfire on that military base just before noon Friday: the blaze was burning 25 acres, prompting an evacuation in that area, the Marine Corps base said. Firefighters were already battling two other blazes on the facility. The new fire, called the Combat or Talega Fire, became the sixth fire still burning in the county as of late Friday.

The week's fires torched more than 31 of San Diego County's 4,206 square miles, according to authorities.

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Mike Mohler, a spokesman for the California Department of Forestry and Fire Protection, said he was "cautiously optimistic" the day would see major gains in bringing the blazes under control.

Firefighters, aided by civilian and military aircraft, had largely contained a few of the fires, but officials said that the 1,200-acre San Marcos/Cocos fire remained "very active" and that two other fires near Marine Corps Base Camp Pendleton were largely uncontained.

The Las Pulgas fire plaguing the sprawling military base had grown to 8,000 acres and was 5% contained, the base said in a statement on Facebook. Some areas of the base had been ordered to evacuate.

Ash and smoke filled the air in many places, making breathing difficult.

So far, injuries have been few: Authorities found a charred body in Carlsbad, but it was unknown whether the person died because of the fire. A Camp Pendleton firefighter suffered heat exhaustion.

Homes, other buildings destroyed

With the fires still burning, even localized damage estimates were hard to come by. But Carlsbad officials say blazes there damaged or destroyed at least 12 homes, two commercial structures and an apartment building.

In all, 176,000 notices of evacuation were sent throughout San Diego County via cell phone calls, e-mails, text messages and landline calls to homes and businesses, county Supervisor Dianne Jacob said.

On Thursday night, 232 people stayed in four shelters, along with 79 dogs, cats and birds, Jacob said.

"Our fire season has begun," Jacob said. She pointed out how January predictions of this year possibly being the worst fire season have "come true."

In the area including San Marcos and the Cocos Fire, 56,000 notices were dispatched, county spokeswoman Sarah Gordon said. But only 11,000 people in that fire area remained evacuated Friday, Cal Fire Capt. Mike Mohler said. The remainder were allowed to return home, Gordon said.

In Escondido, more than 15,000 residents were told to evacuate. The evacuation zone included a 12-story hospital, Palomar Medical Center West, but authorities ultimately told workers there to shelter in place with patients.

Evacuation orders for some 10,000 people in Carlsbad had been lifted, as had similar orders for some of the 5,000 homes evacuated in San Marcos.

Still, thousands of homes across the county are still in jeopardy.

"I've been doing this for 20 years," San Diego County Supervisor Bill Horn told CNN. "This is the worst I've seen."

Images from the fires were jarring.

The night sky glowed orange from towering flames that consumed homes. Whirling columns of flame -- dubbed "firenadoes" or "fire whirls" -- spun across the landscape, in one case nearly devouring a hilltop home.

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Photos: Photos: California wildfires Photos: Photos: California wildfires California wildfires – Residents watch a wildfire near San Diego on Friday, May 16. Wildfires devoured more than 20,000 acres in San Diego County after a high-pressure system brought unseasonable heat and gusty winds to the parched state. Hide Caption 1 of 38 Photos: Photos: California wildfires California wildfires – A paddleboarder watches two helicopters grab water from the Pacific Ocean to fight wildfires near Camp Pendleton, California, on May 16. Hide Caption 2 of 38 Photos: Photos: California wildfires California wildfires – Smoke plumes rise May 16 behind the entrance to Camp Pendleton, a U.S. Marine Corps base. Hide Caption 3 of 38 Photos: Photos: California wildfires California wildfires – A Marine helicopter scoops water from the ocean to fight a wildfire near Camp Pendleton on May 16. Hide Caption 4 of 38 Photos: Photos: California wildfires California wildfires – Flames light up the sky May 16 near Camp Pendleton. Hide Caption 5 of 38 Photos: Photos: California wildfires California wildfires – A helicopter drops water near homes in San Marcos, California, on May 16. Hide Caption 6 of 38 Photos: Photos: California wildfires California wildfires – Marines move military vehicles near the entrance to Camp Pendleton on May 16. Hide Caption 7 of 38 Photos: Photos: California wildfires California wildfires – People look over a canyon ravaged by fire in Carlsbad, California. Hide Caption 8 of 38 Photos: Photos: California wildfires California wildfires – Fire engulfs a structure in Escondido, California, on Thursday, May 15. Hide Caption 9 of 38 Photos: Photos: California wildfires California wildfires – A firefighter pulls a hose on May 15 while battling a wildfire in San Marcos. Hide Caption 10 of 38 Photos: Photos: California wildfires California wildfires – A house in San Marcos burns on May 15. Hide Caption 11 of 38 Photos: Photos: California wildfires California wildfires – A helicopter from the San Diego County Sheriff's Department drops water on flames in the hills of San Marcos, California, on May 15. Hide Caption 12 of 38 Photos: Photos: California wildfires California wildfires – A huge plume of smoke in San Marcos is seen on May 15 from atop Mount Soledad in La Jolla, California. Hide Caption 13 of 38 Photos: Photos: California wildfires California wildfires – The grille of a pickup truck is left melted by a wildfire in San Marcos. Hide Caption 14 of 38 Photos: Photos: California wildfires California wildfires – Smoke rises as a wildfire closes in on houses near San Marcos on May 15. Hide Caption 15 of 38 Photos: Photos: California wildfires California wildfires – Jeff Brown wets down the roof of his Escondido home as a wildfire smolders around it on May 15. Hide Caption 16 of 38 Photos: Photos: California wildfires California wildfires – A helicopter drops retardants onto a wildfire May 15 in San Marcos. Hide Caption 17 of 38 Photos: Photos: California wildfires California wildfires – A wildfire burns near homes and California State University in San Marcos on Wednesday, May 14. Hide Caption 18 of 38 Photos: Photos: California wildfires California wildfires – A house in San Marcos is consumed by a wildfire on May 14. Hide Caption 19 of 38 Photos: Photos: California wildfires California wildfires – Firefighters spray water on a burning building in Carlsbad, California. Hide Caption 20 of 38 Photos: Photos: California wildfires California wildfires – A firefighter puts out a spot fire in San Marcos. Hide Caption 21 of 38 Photos: Photos: California wildfires California wildfires – A plane drops fire retardant over a hot spot in San Marcos on May 14. Hide Caption 22 of 38 Photos: Photos: California wildfires California wildfires – A woman flees a wildfire as it crosses a highway in Carlsbad on May 14. Hide Caption 23 of 38 Photos: Photos: California wildfires California wildfires – A firefighter sprays water onto a fully engulfed home in Carlsbad on May 14. Hide Caption 24 of 38 Photos: Photos: California wildfires California wildfires – A helicopter flies over burning vegetation near homes in Carlsbad on May 14. Hide Caption 25 of 38 Photos: Photos: California wildfires California wildfires – A firefighter puts water on a smoldering fence outside a home in Carlsbad on May 14. Hide Caption 26 of 38 Photos: Photos: California wildfires California wildfires – A woman is escorted to safety May 14 in Carlsbad. Hide Caption 27 of 38 Photos: Photos: California wildfires California wildfires – A Carlsbad police officer turns traffic away as flames rage behind him on May 14. Hide Caption 28 of 38 Photos: Photos: California wildfires California wildfires – A wildfire approaches buildings in Carlsbad on May 14. Hide Caption 29 of 38 Photos: Photos: California wildfires California wildfires – A helicopter drops water near the Rancho Santa Fe neighborhood of San Diego on Tuesday, May 13. Hide Caption 30 of 38 Photos: Photos: California wildfires California wildfires – Trees burn on May 13 as a San Diego wildfire moves through a canyon between Rancho Santa Fe and the Fairbanks Ranch area. Hide Caption 31 of 38 Photos: Photos: California wildfires California wildfires – A wildfire threatens luxury homes in the Fairbanks Ranch area on May 13. Hide Caption 32 of 38 Photos: Photos: California wildfires California wildfires – Firefighters prepare to take on a wildfire in San Diego. Hide Caption 33 of 38 Photos: Photos: California wildfires California wildfires – A helicopter battles a San Diego wildfire on May 13. Hide Caption 34 of 38 Photos: Photos: California wildfires California wildfires – Firefighters arrive to assist local personnel in San Diego on May 13. Hide Caption 35 of 38 Photos: Photos: California wildfires California wildfires – Smoke rises from a canyon where a San Diego wildfire burned on May 13. Hide Caption 36 of 38 Photos: Photos: California wildfires California wildfires – Firefighters watch from a ridge as a helicopter drops retardant on flames in San Diego on May 13. Hide Caption 37 of 38 Photos: Photos: California wildfires California wildfires – Billowing smoke rises as firefighters trek up the hills to battle a San Diego fire on May 13. Hide Caption 38 of 38

Firenadoes are spinning columns of flame fed by fuel drawn into the air by naturally occurring vortices created by fire, CNN meteorologist Indra Petersons said. They can spit out winds as powerful as an EF-2 tornado, she said.

In video shot by Jeb Durgan and Byron Bowman, a helicopter wheeled over homes, dumping fire retardant just yards from a burning canyon choked with flames. Smoke obscured the road the two were driving on.

"If you imagine standing next to a barbecue or a campfire and multiply that by a hundred, that's what it felt like for a few seconds," Bowman said.

The fire, he said, made a "roar like a lion."

Two are investigated for arson

While the causes of the wildfires remain unclear, arson has been a primary suspicion among residents.

Escondido police Thursday night arrested a 19-year-old man and a 17-year-old juvenile, both of Escondido, in connection with arson-related charges stemming from brush fires along Escondido Boulevard and Kit Carson Park, authorities said.

Community members observed the fire and put it out, Dumanis said.

Witnesses said two people "appeared to be involved in setting small fires," Escondido Police Lt. Neal Griffin said.

Police don't have reason yet to think the teens were involved in the other fires, but "obviously we will be exploring that possibility," Griffin said.

Evolution of a disaster

The wave of wildfires started Tuesday with the Bernardo Fire in San Diego County. The next day, new blazes popped up -- each one separate from the others, each posing its own dangers.

Cal Fire Director Ken Pimlott said that the amount of fire activity statewide so far this year has been "unprecedented."

Here's where some of the major California fires stood as of Friday, according to Cal Fire:

The Cocos Fire in San Marcos

• 3,018 acres burned

• 10% of the fire has been contained

• The fire is still very active, with evacuations in effect.

The Tomahawk Fire at Marine Corps Base Camp Pendleton

• 6,300 acres burned

• 23% of the fire has been contained

• A Camp Pendleton firefighter was being treated Thursday for heat exhaustion.

Las Pulgas Fire at Marine Corps Base Camp Pendleton

• 8,000 acres burned

• 5% of the fire has been contained

• Camp Las Pulgas and Camp Margarita were ordered to evacuate.

The Bernardo Fire in San Diego

• 1,548 acres burned

• 90% of the fire has been contained

• Authorities believe the blaze will be fully contained Friday. Evacuations were lifted.

The Poinsettia Fire in Carlsbad

• 400 acres burned

• 90% of the fire was contained Friday.

The Combat or Talega Fire at Marine Corps Base Camp Pendleton

• 25 acres burned

• 0% of the fire was contained Friday.