(SANTA ROSA, Calif.) -- Massive wildfires sweeping through California have killed at least 21 people and damaged thousands of homes, businesses and other buildings, authorities said.
Firefighters were still battling 22 wildfires in multiple California counties Wednesday morning. Intensified by strong winds, the flames have charred about 170,000 acres of land, damaged or destroyed at least 3,500 structures and forced nearly 20,000 residents to evacuate, according to the California Department of Forestry and Fire Protection.
The causes of the fires are unknown.
More than 2,700 firefighters and support personnel are battling the fires, according to the National Interagency Fire Center. California Gov. Jerry Brown has declared a state of emergency for Napa, Sonoma and Yuba counties in Northern California.
With firefighters stretched thin throughout the state, federal agencies as well as neighboring Nevada and nearby Washington state are assisting with resources.
St. Joseph Health said 168 patients have been treated, many for burns and smoke inhalation, at three of its hospitals in Napa and Sonoma counties as of Monday night.
An additional 560 people were missing in Sonoma County as of Wednesday morning, according to the sheriff's office.
Meanwhile, at least 7,000 people were without power Wednesday in Napa County alone.
With mandatory evacuation orders still in place, many residents in the affected areas have been warned not to return to their homes until further notice.
"Life is more important than property," Sonoma County Sheriff Robert Giordano said at a press conference Tuesday.
He said he thinks the wildfires will be "one of the worst natural disasters in California history."
Southern LNU Complex fires
The so-called Atlas, Nuns and Patrick fires are considered branches of one giant blaze in Napa, Solano and Sonoma counties — collectively known as the Southern LNU Complex — according to the California Department of Forestry and Fire Protection.
Mandatory evacuations and road closures were underway in Napa, Solano and Sonoma counties, the heart of California's wine country, as the flames threatened thousands of structures.
The Atlas fire has scorched 42,349 acres in Napa and Solano counties since the inferno began Sunday night, and just 3 percent of the blaze was contained Wednesday morning. The enormous fire has destroyed 125 structures.
The Nuns fire has charred 7,626 acres in Sonoma County since Sunday night, and it was just 1 percent contained Wednesday morning.
Meanwhile, the Patrick fire has burned 9,523 acres in Napa County since Sunday night, and just 2 percent of it was contained Wednesday morning.
Central LNU Complex fires
The Tubbs and Pocket fires make up another enormous blaze, known as the the Central LNU Complex, in Napa and Sonoma counties, according to the California Department of Forestry and Fire Protection. More than 16,000 structures are threatened.
The Tubbs fire has singed 28,000 acres in Napa County since Sunday night. The fire has destroyed 571 structures.
Meanwhile, the Pocket fire has scorched 1,800 acres in Sonoma County since Monday morning.
Mendocino Lake Complex fires
The Redwood/Potter fires and the Sulphur fire make up a giant blaze, known as the Mendocino Lake
Complex, in Lake and Mendocino counties, according to the California Department of Forestry and Fire Protection.
The Redwood/Potter fires have charred 29,500 acres in Mendocino County since Sunday night, and was just 5 percent contained Wednesday morning.
The Sulphur fire has burned 2,500 acres in Lake County since late Sunday night, and was 30 percent contained by Wednesday morning.
Wind Complex fires
The Cascade, La Porte, Lobo and McCourtney fires make up one huge blaze in Butte, Nevada and Yuba counties, collectively known as the Wind Complex, according to the California Department of Forestry and Fire Protection.
The Cascade fire has scorched 12,349 acres in Yuba County since it began Sunday morning, and it was 20 percent contained Wednesday morning, according to the California Department of Forestry and Fire Protection.
La Porte fire has charred 3,700 acres in Butte County since the blaze ignited early Monday morning, and it was 15 percent contained by Wednesday morning, according to the California Department of Forestry and Fire Protection.
The Lobo fire has burned 857 acres in Nevada County since early Monday morning and 30 percent was contained Wednesday morning.
Meanwhile, the McCourtney fire has singed 76 acres in Nevada County since early Monday morning, and was 65 percent contained Wednesday morning.
Canyon 2 fire
The Canyon 2 fire has scorched 8,000 acres in Southern California's Orange County since the flames started Monday morning. It was 45 percent contained Wednesday morning, according to the California Department of Forestry and Fire Protection.
At least 3,000 residents were evacuated in and around Anaheim as thousands of structures were threatened by the blaze.
The Cherokee fire has charred 7,500 acres in Butte County since Sunday night, and it was 40 percent contained Wednesday morning, according to the California Department of Forestry and Fire Protection.
The 37 fire has burned 1,650 acres in Sonoma County since it started Monday afternoon. It was 65 percent contained by Wednesday morning, according to the California Department of Forestry and Fire Protection.
What's ahead for California
A cold front is expected to sweep through much of California on Wednesday, bringing more gusty winds and lower humidity, according to ABC News meteorologists. The weather conditions have local authorities concerned about "aggressive" fire behavior.
The National Weather Service has issued red flag warnings for Central and Northern California for Wednesday through Thursday. Fire weather watches were issued for Southern California for Thursday through Saturday.
As firefighters work to snuff the raging blazes, Sonoma County Sheriff's Sgt. Spencer Crum told ABC News the county has asked everyone to "help us out."
The wind's shifting gusts that helped the flames spread appeared to have subsided, he added.
"The night before this, we had 60 mph winds, which is the reason why you have such devastation here,"
Crum told ABC News chief anchor George Stephanopoulos in an interview Tuesday on "Good Morning America."
Crum confirmed that the alert system put in place gave residents ample time to evacuate and likely prevented many deaths.
"We have a subscription service where we can alert our residents, and we did that right away, trying to notify everybody where the fire was, where it was going and how fast it was going, and I think it saved a lot of lives," he said.
The sheriff's sergeant conceded that it could take a long time for communities to bounce back.
"We have a lot of rebuilding here," Crum said.
Santa Rosa resident Jeff Okrepkie said he fled his home of five years knowing that it could very well be leveled when he returned.
Okrepkie said he and his wife tried their best to gather their most precious documents, photos and mementos, but it was impossible to grab everything in time.
Mike Turpen, 38, said he was at a bar in the Glen Ellen area of Sonoma County when someone stormed in wearing a smoke mask and yelled, "Fire!" He said he drove through the flames in his pickup truck with hopes of saving his home.
Turpen said his yard was scorched and still flaming in some spots, but he managed to keep his home from burning down.
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