Los Angeles (CNN) Robin Navickas left behind her hearing aids and even her shoes when the Saddleridge Fire was creeping toward her home. When she returned hours later, everything was reduced to piles of ash.

"She just kept thinking that some things will still be there in the middle of the house and I kept trying to tell her no," her son Errol Navickas told CNN outside his mother's home. "The front of the house is all that's there."

The wildfire in northern Los Angeles has destroyed 31 homes and burned more than 7,500 acres, the Los Angeles Fire Department said. More than 1,000 firefighters have been battling the blaze, but it remains 13% contained as of Friday.

A firefighter suffered an injury to his eye, but no deaths have been linked to the fire, Los Angeles Mayor Eric Garcetti told reporters.

The home where Errol Navickas and his mother lived in the Granada Hill neighborhood was destroyed.

About 100,000 people were forced to evacuate homes in several Los Angeles neighborhoods when the blaze began spreading rapidly, fueled by strong Santa Ana winds and low humidity.

In Porter Ranch, Andro Mammo drove his siblings away from the flames as fast as he could when the fire reached their home.

"When I looked out in my backyard, I saw flames and I saw how close it was, and my number one instinct wasn't to grab clothes or anything, but it was to get my little brother and my little sister," Mammo recalled.

A photo taken by Andro Mammo shows the Porter Ranch neighborhood in Los Angeles engulfed in flames.

Some residents have been allowed back in or near their homes, but city officials said the danger is not over yet.

"It's not the fire itself but the danger of wind that can bring an ember blowing it someplace and seeing entire neighborhood overnight getting lit up," Garcetti said.

The Saddleridge fire is just one of the several blazes in Southern California fueled by one of those fires has left at least one person dead, and many parts of the region are under red-flag warnings — meaning there's a high risk of fire — into Saturday afternoon.

The Saddleridge Fire jumped two freeways

The Saddleridge Fire started around 9 p.m. ET and jumped the 210 and 5 freeways, and some parts those roads and the 405 were closed as orange embers lit up the night sky. By late Thursday it had gutted 60 acres; just hours later, it had grown to more than 4,000 acres, fire officials said.

The fire's cause was not immediately known.

Hector Landeros, who lives in northern Los Angeles' Sylmar neighborhood, said he heard fire trucks and police cruisers speeding through the streets as the massive flames got closer.

"In some areas, the streets have started to empty but at the front lines people are watching, waiting on the sidewalk not really knowing what to do," he told CNN early Friday. "There are a lot of people trying to get into their neighborhoods."

The Saddleridge fire flares up near a firefighter in Los Angeles' Porter Ranch neighborhood.

Shaun Butch said he saw flames on both sides of the freeway while driving on Interstate 5.

"Everything was engulfed in smoke and visibility was so low it was hard to drive. Everyone on the Interstate 5 north was stopped and trapped. Still was able to barely get through on the Interstate 5 north."

Patsy Zamora said as she drove on the freeway with the fire next to the truck route, she could feel the heat through the windows.

A helicopter drops water while battling the Saddleridge fire in northern Los Angeles on Friday.

In Porter Ranch, firefighters from neighboring Orange County arrived just in time to stop the fire from charging into Francisco and Flora Villalta's house Friday morning.

A CNN crew watched as firefighters shot water through the spaces of the Villaltas' fence — halting the flames right at the property's edge after they came up the nearby hills.

"I was just crying, because (I thought) our house is gone," Flora Villalta said. "But then ... the fire truck (came). We were praying for someone."

A firefighter sprays water as a fire inches toward a home in Los Angeles' Porter Ranch area on Friday morning.

In Sylmar, Mojdan Darabi's husband was spraying their house and yard with a garden hose, CNN affiliate KABC reported. They both stood outside, anxiously watching flames in the nearby hillsides.

"Yes, I'm worried, but I'm just shooting water everywhere to stop the fire from over here," the husband said.

Poor air quality prompted school closures

Classes were canceled at about 40 schools in the Los Angeles area after poor air quality was reported, Sgt. Rudy Perez with Los Angeles School Police Department said.

Perez said all the schools in the San Fernando Valley were closed midday and all after-school activities were canceled Friday.

A number of colleges and other schools also closed Friday because of the fire, including California State University Northridge and Los Angeles Mission College in Sylmar.

The Los Angeles Unified school district closed dozens of schools and said bus service throughout the district would be delayed.

A woman leaves her home with her cat as the Saddleridge Fire threatens homes in Los Angeles' Granada Hills area on Friday.

It's one of multiple fires in the region

The Saddleridge Fire is one of several burning in Southern California.

Another blaze — the Sandalwood Fire in Calimesa , some 70 miles east of Los Angeles — has killed at least one person, according to the Riverside County Sheriff's Department. Details about that death weren't immediately available.

The fire, which started as a trash fire that spread to vegetation, has destroyed at least 76 structures since it began Thursday afternoon, Riverside County Sheriff Chad Bianco said. It has burned more than 820 acres and was at least 10% contained by Friday.

The Sandalwood Fire in Calimesa has destroyed 74 structures.

Capt. Fernando Herrera of Cal Fire Riverside told CNN affiliate KABC the blaze "completely went out of control" due to the Santa Ana winds

"It started just eating up vegetation as fast as the eye can see," he said.

Residents are under mandatory evacuation orders, and 250 firefighters are assigned to the area.

The fire has burned several buildings in the Villa Calimesa Mobile Home Park.

Less than 20 miles away in Moreno Valley, the Reche Fire has burned at least 350 acres and was 40% contained. The fire went from 100 to 200 acres in about 90 minutes, before nearly doubling two hours later. Mandatory evacuations have been issued in surrounding areas, and the cause is under investigation.

Southern California Edison cut power to almost 24,000 customers Thursday to prevent wildfires caused by high winds downing live power equipment.

In Northern California, utility Pacific Gas & Electric also cut power to hundreds of thousands of customers this week , similarly hoping to prevent wildfires during windy conditions.

CORRECTION: An earlier version of this story misspelled the name of Los Angeles Police Chief Michel Moore and misidentified the agency he leads.