(CNN) Fanned by scorching heat, windy conditions and a five-year drought, a pair of California wildfires has burned tens of thousands of acres in southern and central parts of the state.

On Tuesday, acting California Gov. Tom Torlakson issued emergency proclamations for both fires in Los Angeles and Monterey counties. Torlakson is standing in for Gov. Jerry Brown, who is attending the Democratic National Convention.

In Southern California, the so-called Sand Fire has set more than 37,700 acres of the Santa Clarita Valley ablaze. The fire was 25% contained as of Tuesday evening, according to the Los Angeles County Fire Department.

One person has died in the blaze, at least 18 homes have burned and 20,000 residents had been evacuated, according to fire authorities. On Monday evening, the fire department announced that most of the evacuated residents have been allowed to re-enter the area.

Temperatures hit 101 degrees in the area and dried brush from the parched, drought conditions has helped to spread the fire to about 57 square miles -- a size that is bigger than the city of San Francisco (which is 47 square miles).

Photos: Sand Fire scorches California A hillside erupts in flame in Placerita Canyon in Santa Clarita, California on Monday, July 25. Fire officials said the so-called Sand Fire was growing at the rate of 10,000 acres per day and could potentially spread in any of three directions depending on changing winds. The wildfire has already scorched more than 33,000 acres and destroyed at least 18 homes. Hide Caption 1 of 16 Photos: Sand Fire scorches California Firefighters monitor a flareup as they work to stop the advance of the Sand Fire near the town of Acton, California. Hide Caption 2 of 16 Photos: Sand Fire scorches California Residents return to a home that was destroyed by fire in Santa Clarita. Hide Caption 3 of 16 Photos: Sand Fire scorches California A fireman grabs his hose to battle a fire off Placerita Canyon Road in Santa Clarita. Hide Caption 4 of 16 Photos: Sand Fire scorches California The ruins of a home destroyed by the blaze in Santa Clarita. Hide Caption 5 of 16 Photos: Sand Fire scorches California A plane drops fire retardant in the mountains near Santa Clarita. Hide Caption 6 of 16 Photos: Sand Fire scorches California Burned-out film sets at the Sable Ranch. The ranch had Old West-style buildings seen in many movies and television shows. Hide Caption 7 of 16 Photos: Sand Fire scorches California A burned pirate sculpture stands in the charred landscape in Santa Clarita. Hide Caption 8 of 16 Photos: Sand Fire scorches California A helicopter makes a drop on a wildfire near Placerita Canyon Road in Santa Clarita on Sunday. Hide Caption 9 of 16 Photos: Sand Fire scorches California Flames from the Sand Fire are reflected in a backyard swimming pool on Saturday in Santa Clarita.

Hide Caption 10 of 16 Photos: Sand Fire scorches California Flames close in on homes near Santa Clarita. Hide Caption 11 of 16 Photos: Sand Fire scorches California A scorched landscape, left smoldering from the Sand Fire. Hide Caption 12 of 16 Photos: Sand Fire scorches California A firefighter hoses down burning pipes near a water tank. Hide Caption 13 of 16 Photos: Sand Fire scorches California Firefighters of the Texas Canyon Hotshots fight the Sand Fire. Hide Caption 14 of 16 Photos: Sand Fire scorches California Firefighters with the Valyermo Hotshots of the Angeles National Forest get ready to go back to work on Little Tujunga Canyon Road in Santa Clarita. Hide Caption 15 of 16 Photos: Sand Fire scorches California A marker at the entrance of the Angeles National Forest. Hide Caption 16 of 16

Nearly 3,000 firefighters are battling the flames in extremely volatile conditions. The fires are rolling up and down the canyons in what looks like a wall of flames. Firefighters are having to navigate steep terrains in extremely dry conditions in heavy smoke that clouded the area.

A time-lapse of the Sand Fire shows its progression and fury through the California hills. @CNN #SandFire pic.twitter.com/cfnVxKaDMh — CNN Weather Center (@CNNweather) July 25, 2016

Towering columns of smoke could be seen from miles away, highlighting the dangers of the Sand Fire, named for the area's Sand Canyon. Ash rained down and red skies became the backdrop.

Joey Marron, an inspector with the Los Angeles County Fire Department, said Tuesday the fight was going pretty well.

"We set some backfires overnight in some of our areas of concern and this gave us space to contain the fire. We should be good, if the winds don't pick up. It's still very hot out there."

Fire takes a heavy toll

The extent of the fire's damage could be seen from satellite images that showed the burn scars left on the hills and canyons.

The wildfire broke out Friday afternoon and quickly spread about 10,000 acres a day.

Of the 18 homes destroyed, three of them belonged to firefighters and four of the structures had been occupied by Forest Service employees, reported CNN affiliate KABC-TV in Los Angeles

The fire also burned parts of the Sable Ranch, where many movies and TV shows were shot, reducing film sets to charred piles of burnt wood and metal. Productions that used the ranch included "The A Team," "Invisible Man" with Chevy Chase," "Terror From Above" and "Robin Hood: Men in Tights," according to the ranch website.

Sable Ranch, where many movies and TV shows were shot, was lost in the Sand Fire.

"It tore through here in a blink," Derek Hunt manager of the Sable Ranch told CNN.

Hunt stood atop a ridge looking over canyons filled with film sets.

"I've been so busy it hasn't hit me what we lost, all this history," he said, swallowing hard in 100 degree choking heat. "I'm going to rebuild. We have to."

Challenges in fighting the flames

Helicopters circled the blaze, dousing flames with water. Cal Fire helicopters flew back and forth between the ocean, where they collected water, and the Santa Clarita area, where they dumped the water on the fire lines.

Two @LACoFireAirOps Firehawk helicopters made drops overnight to protect homes on the #SandFire (📷CoreyFredrickson) pic.twitter.com/wM3AYnNP1R — LACoFireAirOps (@LACoFireAirOps) July 23, 2016

After spotting drone activity in the fire area, authorities warned that the small aircraft could interfere with firefighting efforts and issued a FAA temporary flight restriction.

A smoke advisory warning of the unhealthy air quality in portions of the Santa Clarita Valley and the San Gabriel Mountains has been issued. The local air pollution control agency warned that people in the areas affected by smoke should avoid vigorous outdoor or indoor exertion.

There are also concerns that the shifting wind could exacerbate the fire, as they are expected to remain in the 25 to 30 miles per hour range Monday night, reported KABC. But the winds are expected to weaken into Tuesday.

Major fire burns in Monterey County

Firefighters in central California are grappling with similar challenges in another major wildfire.

That blaze in Monterey County, called the Soberanes Fire, has burned more than 23,500 acres along the California coast between the scenic areas of Carmel and Big Sur. The fire is bigger than the size of Manhattan.

Firefighters have contained 10% of the fire, which began Friday, according to Cal Fire.

Time lapse of the 19,311 acre #SoberanesFire burning in Monterey Co. Fire activity above marine layer very active. pic.twitter.com/PFJu7A7n29 — CAL FIRE PIO Berlant (@CALFIRE_PIO) July 26, 2016

Oliver Bates has spent the last three nights at a Red Cross shelter after fleeing his home. He told CNN affiliate KSBW, which is based in Monterey, that he had tried to save his house from the fire.

"I only left when it got really bad," Bates said. "It was raining fire from the sky."

He still didn't know what happened to his house.

Bates is one of the 300 residents who've left their homes as mandatory evacuations have been issued in several communities, including the Palo Colorado neighborhood, which sits between Carmel and Big Sur, as well as southern portions of the Carmel Highlands area. No injuries have been reported as nearly 3,000 firefighters tried to get control of the fire.

The wildfire made its relentless march down the central coast, destroying at least 20 homes.

The smoke from the fire could be seen in Silicon Valley (about a hundred miles north) and Lake Tahoe (about 300 miles east). Air quality health alerts have been issued in the regional areas.