(CNN) It's one word the National Weather Service in Los Angeles doesn't want Southern California residents to overlook -- extreme.

As in, this isn't just another red flag warning -- meaning winds, temperatures and humidity are ripe for fire danger. It's an extreme red flag warning.

The weather service in using the term for the first time to convey that the fire conditions expected this week "have not been seen in recent memory."

Hurricane-force winds -- the kinds that knock down power lines and trees -- are expected to blow across bone-dry vegetation on Wednesday, and the weather service is warning there is a danger of very rapid fire spread.

"Residents in high fire risk areas should be ready and set to evacuate if emergency officials say so," the weather service office said.

Tom Fisher with the weather service said the NWS was not making a new category of warnings.

"Extreme red flag is not a grade, but it was super important that we get the residents' attention," he said. "This is the fourth event that we've had, it's been a very long, dry spell. And there's no rain in sight."

This isn't the first time the National Weather Service has tried to convey danger by adding enhanced language to an alert. In 1999, they issued a tornado "emergency" for Moore, Oklahoma, before an EF5 tornado that killed 36 people. In 2005, an NWS forecaster in Louisiana warned of conditions that could make the area "uninhabitable" before Hurricane Katrina killed more than 3,600 people and wrought around $161 billion of damage in the Gulf Coast states.

Multiple fires in California

More than 26 million people from California to Arizona are under red flag warnings Tuesday as firefighters deal with blazes already burning in California's wine country and in the Los Angeles area.

Photos: Wildfires scorch California Photos: Wildfires scorch California Firefighters spray water on a backfire while battling the spread of the Maria Fire on Friday, November 1. It is just one of the numerous wildfires in California right now. Hide Caption 1 of 56 Photos: Wildfires scorch California A firefighter works at containing the Maria Fire in the hills near Ventura, California, on November 1. Hide Caption 2 of 56 Photos: Wildfires scorch California Firefighters spray water onto a tree while fighting the Maria Fire in Ventura County, California, on November 1. Hide Caption 3 of 56 Photos: Wildfires scorch California A long-exposure photo shows the Maria Fire as it races across a hillside in Santa Paula, California, on November 1. Hide Caption 4 of 56 Photos: Wildfires scorch California Firefighters watch the progress of a backfire near Somis. Hide Caption 5 of 56 Photos: Wildfires scorch California The remains of the Louis Robidoux Nature Center keep smoldering after the structure was destroyed by a wildfire in Riverside, California. Hide Caption 6 of 56 Photos: Wildfires scorch California A firefighter sprays down the smoldering remains of a burning home in San Bernardino, California, on Thursday, October 31. It was affected by the Hillside Fire. Hide Caption 7 of 56 Photos: Wildfires scorch California Marco Alcaraz uses a garden hose to try to slow down the advance of the Easy Fire in Simi Valley. Hide Caption 8 of 56 Photos: Wildfires scorch California Firefighters work to prevent a blaze from spreading to other homes in San Bernardino. Hide Caption 9 of 56 Photos: Wildfires scorch California An Air Force One from Ronald Reagan's presidency sits on display as the Easy Fire burns near Reagan's presidential library on October 30. Hide Caption 10 of 56 Photos: Wildfires scorch California Firefighters brace themselves for incoming fire retardant as they battle the Easy Fire in Simi Valley. Hide Caption 11 of 56 Photos: Wildfires scorch California Fabio Losurdo comforts his horse, Smarty, at a ranch in Simi Valley on October 30. Hide Caption 12 of 56 Photos: Wildfires scorch California Flames approach the backyards of mobile homes in Jurupa Valley, California, on October 30. Hide Caption 13 of 56 Photos: Wildfires scorch California Laura Horvitz, right, and Robyn Phipps help rescue goats from a ranch near the Reagan Presidential Library. Hide Caption 14 of 56 Photos: Wildfires scorch California Health care workers evacuate the Riverside Heights Healthcare Center on October 30. Hide Caption 15 of 56 Photos: Wildfires scorch California Inmate firefighters battle the Kincade Fire near Healdsburg, California, on Tuesday, October 29. Hide Caption 16 of 56 Photos: Wildfires scorch California A home between Healdsburg and Windsor is surrounded by charred ground on October 29. Hide Caption 17 of 56 Photos: Wildfires scorch California From left, California Gov. Gavin Newsom, Los Angeles City Councilman Mike Bonin and Los Angeles Mayor Eric Garcetti tour a burned home in Brentwood, California, on October 29. Hide Caption 18 of 56 Photos: Wildfires scorch California Firefighters work near the Getty Center in Los Angeles on Monday, October 28. Hide Caption 19 of 56 Photos: Wildfires scorch California Thousands of Los Angeles residents were forced to evacuate their homes because of the Getty Fire. Hide Caption 20 of 56 Photos: Wildfires scorch California Los Angeles County firefighter Collin Bashara rests near his truck on October 28. Hide Caption 21 of 56 Photos: Wildfires scorch California Smoke from the Kincade Fire hangs over Healdsburg as farm animals graze in a pasture on October 28. Hide Caption 22 of 56 Photos: Wildfires scorch California A man walks past a burning home in Los Angeles on October 28. Hide Caption 23 of 56 Photos: Wildfires scorch California Fire crews walk along a blackened ridge as they battle the Getty Fire in Los Angeles. Hide Caption 24 of 56 Photos: Wildfires scorch California Firefighters battling the Kincade Fire spray water at a home in Windsor on Sunday, October 27. Hide Caption 25 of 56 Photos: Wildfires scorch California Firefighters burn fuel around a home in Windsor in an effort to save it from the Kincade Fire. Hide Caption 26 of 56 Photos: Wildfires scorch California Dr. Emily Putt, a veterinarian who helps rescue horses from fire zones, comforts a horse as the Kincade Fire burns in Healdsburg on October 27. Hide Caption 27 of 56 Photos: Wildfires scorch California A firefighter passes a burning home as the Kincade Fire rages in Healdsburg on October 27. Hide Caption 28 of 56 Photos: Wildfires scorch California Vines smolder in a cloud of smoke in Healdsburg. Hide Caption 29 of 56 Photos: Wildfires scorch California Flames from the Kincade Fire consume a home in Healdsburg. Hide Caption 30 of 56 Photos: Wildfires scorch California A team of firefighters put out a smoldering vine in Healdsburg. Hide Caption 31 of 56 Photos: Wildfires scorch California The Soda Rock Winery burns in the Kincade Fire. Hide Caption 32 of 56 Photos: Wildfires scorch California Firefighters from the Dry Creek Rancheria remove an American flag in Healdsburg. Hide Caption 33 of 56 Photos: Wildfires scorch California A firefighter watches over a structure as the Kincade Fire threatens Chalk Hill Road in Healdsburg. Hide Caption 34 of 56 Photos: Wildfires scorch California A firefighter sets a backfire along a hillside in Healdsburg on Saturday, October 26. Hide Caption 35 of 56 Photos: Wildfires scorch California A line of fire snakes along a hillside as firefighters light backfires to slow the spread of the Kincade Fire near Geyserville, California, on October 26. Hide Caption 36 of 56 Photos: Wildfires scorch California Sodhi Singh closes up his Chevron station shortly after losing power in Healdsburg on October 26. In an attempt to avoid any more catastrophic wildfires, Pacific Gas & Electric began shutting down the power to about 940,000 customers, citing a historic wind event in northern and central parts of the state. Hide Caption 37 of 56 Photos: Wildfires scorch California A backfire set by firefighters burns along a hillside in Healdsburg. Hide Caption 38 of 56 Photos: Wildfires scorch California Sandy Beddow evacuates Healdsburg with her dog. Hide Caption 39 of 56 Photos: Wildfires scorch California Firefighters set a backfire along a hillside in Healdsburg. Hide Caption 40 of 56 Photos: Wildfires scorch California Firefighters hose down a burning house in Agua Dulce, California, on Friday, October 25. It was affected by the Tick Fire, which broke out near Santa Clarita. Hide Caption 41 of 56 Photos: Wildfires scorch California Orange County firefighters put out remaining hot spots from a brush fire in San Clemente, California, on October 25. Hide Caption 42 of 56 Photos: Wildfires scorch California A firefighting aircraft intervenes over Sonoma County, California, where the Kincade Fire was burning on October 25. Hide Caption 43 of 56 Photos: Wildfires scorch California A firefighter sprays water on a burning home in Sonoma County on Thursday, October 24. Hide Caption 44 of 56 Photos: Wildfires scorch California A Los Angeles County firefighter monitors the area as the Tick Fire burns near homes in Canyon Country on October 24. Hide Caption 45 of 56 Photos: Wildfires scorch California The Kincade Fire burns in the Jimtown community of Sonoma County on October 24. Hide Caption 46 of 56 Photos: Wildfires scorch California A firefighter works the scene of a burned-out home in Santa Clarita on October 24. Hide Caption 47 of 56 Photos: Wildfires scorch California Brandon Mani covers his face from the smoke as he walks along Highway 14 in Santa Clarita. Hide Caption 48 of 56 Photos: Wildfires scorch California A helicopter passes a smoke plume on October 24. Hide Caption 49 of 56 Photos: Wildfires scorch California A structure continues to burn after the Kincade Fire moved through Geyserville on October 24. Hide Caption 50 of 56 Photos: Wildfires scorch California Geyserville, about 80 miles north of San Francisco, is among the communities under mandatory evacuation order. Hide Caption 51 of 56 Photos: Wildfires scorch California Two firefighters discuss a plan while battling the wildfire in Geyserville. Hide Caption 52 of 56 Photos: Wildfires scorch California The sun rises above a smoke-filled valley in Geyserville on October 24. Hide Caption 53 of 56 Photos: Wildfires scorch California A fire whirl whips across dry brush as the Kincade Fire spreads through Sonoma County on October 24. Hide Caption 54 of 56 Photos: Wildfires scorch California Trees burn as the fire engulfs a hillside in Geyserville. Hide Caption 55 of 56 Photos: Wildfires scorch California Embers fly across a roadway in Jimtown on October 24. Hide Caption 56 of 56

The threats include:

from late Tuesday night into Wednesday, the National Weather Service in Los Angeles said. • A "remarkable and dangerous" Santa Ana winds event in Southern California -- perhaps the strongest this season -- is expected to bring gusts of 60-70 mph in the valleys and up to 80 mph in the mountainsfrom late Tuesday night into Wednesday, the National Weather Service in Los Angeles said.

• Strong winds Tuesday afternoon in Northern California, with gusts up to 50 mph, the weather service's Storm Prediction Center says

The worsening conditions come as firefighters across the state battle at least 11 wildfires that have combined to leave thousands of people under evacuation orders.

On the west side of Los Angeles, where the Getty Fire has charred more than 650 acres since Monday, the expected winds mean roughly 20,000 people under evacuation orders there "will not be returning to their homes this evening," Mayor Eric Garcetti said.

"Stay away until we lift that order," Garcetti said in a news conference Tuesday morning.

Southern California: The Getty Fire

In Los Angeles, the Getty Fire has destroyed at least eight homes since flaring up early Monday, officials say.

The area affected, west of Interstate 405, is known for its celebrities and high-value homes. NBA star LeBron James was among the many residents who evacuated

Nancy Cochran, who left her home in the Mandeville Canyon neighborhood, was among about 100 people who congregated at a makeshift evacuation center at the Westwood Recreation Center.

She told CNN affiliate KABC she had just recently lost her husband of 65 years.

"It's unreal. ... My husband just died, and now this," she told KABC on Monday.

"I'm living in where it's always burned, and it's burning today. So hopefully I'm going home to a home."

At least 16 schools in the Los Angeles Unified School District will remain closed Tuesday because of fire conditions, a news release from the district said. Transportation to and from the schools will be canceled and absences will not be counted against students' records, the release said.

Around 40 miles north, the Tick Fire has burned over 4,600 acres but had reached around 86% containment as of Tuesday morning, according to the Cal Fire incident map. The fire started Thursday and quickly grew to 4,300 acres by Friday, fueled by strong winds.

Northern California: The Kincade Fire

The Kincade Fire, the state's largest active wildfire, has scorched more than 76,100 acres in and around Northern California's Sonoma County since last week.

Firefighters have contained only 15% of the blaze, according to the California Department of Forestry and Fire Protection's fire map. More than 180 structures have been destroyed, 86 of which were single-family residential structures, a CAL FIRE spokesman said.

The NWS said in a Tuesday news conference that red flag conditions will continue until about 4 p.m. Wednesday, but winds will begin to die down Tuesday night.

Weather will begin to look "more favorable" he said toward the end of the week but there is still no rain in the forecast.

The fire started October 23 and quickly spread, an incident report from Cal Fire said.

Driven by hurricane-force winds, the fire grew at a rate of one football field every three seconds when it first ignited, CNN meteorologist Brandon Miller said.

The Kincade Fire burns in the hills near Middletown in California's Lake County on Tuesday.

Up to 186,000 residents were under evacuation orders, officials said. Tuesday afternoon, officials announced they were lifting evacuation orders in parts of the county.

About 2,400 people returned to their homes, Sonoma County Sheriff Mark Essick said in the news conference Tuesday night.

"Many of these people are still returning to homes that are without power because of the PG&E power shutoff," he said. "So we want people to be vigilant, be aware communication may not be great."

There were three reports of looting in evacuated areas, Essick said. In addition to those incidents, three people have been arrested for unauthorized entry, the sheriff said.

California Highway Patrol Capt. Aristotle Wolfe urged people to be smart in the face of dangerous fire conditions. He told reporters he pulled over a motorist who threw a cigarette butt onto a freeway near Petaluma on Tuesday.

"This is no time to add to the problem," Wolfe said. "Please help us subtract from it."

Firefighters from San Mateo work to extinguish flames from the Kincade Fire.

Two first responders have been hospitalized because of burns during the Kincade Fire, officials said. One person suffered a serious burn injury and was flown to UC Davis Medical Center, and a second person was treated at a local hospital for a minor burn, Cal Fire spokesman Jonathan Cox said.

The cause of the Kincade fire is under investigation.

Companies plan to turn off power again

Because of the fire risks, utility companies are again planning to intentionally shut off power to hundreds of thousands of people Tuesday and Wednesday, hoping to lessen the chances their equipment will start or contribute to blazes.

Pacific Gas & Electric said it intends to interrupt power to about 596,000 customers in 29 counties in central and northern California by Tuesday night, with some outages starting in the morning.

In Southern California, 205,000 customers in seven counties are under consideration for possible power shutoffs, Southern California Edison said.

Residents in many areas in the state just had their power restored following severe winds and concerns for fire hazards over the weekend.

Community resource centers are open during the shutoffs in Northern California to give people a place to charge their phones, use restrooms and sit in air conditioning, a tweet from PG&E said.

California utilities -- especially PG&E -- have been more aggressive this year in cutting power as a means of preventing wildfires caused by high winds downing live power equipment. This comes after PG&E came under criticism in recent years for the role of its equipment in a series of catastrophic wildfires across the state , including the deadly 2018 Camp Fire.