(CNN) -- Firefighters are facing difficulties battling three fast-moving wildfires north of Napa, California, totaling at least 44,000 acres as of early Monday, officials said.
The blazes have become a rapidly evolving crisis as Gov. Jerry Brown on Monday issued an emergency proclamation for three counties and local officials are working up a strategy to confront the fires, which show no sign of ending amid high winds and hot and dry weather.
More than 50 structures have burned due to the rapidly moving Atlas Fire in Napa, said Napa County Fire Chief Barry Biermann. Complicating firefighting efforts are low humidity and a lack of resources, he added.
"As of right now, with these conditions, we can't get in front of this fire and do anything about the forward progress," he said, adding that resources from across California were to begin arriving in the area later Monday.
The wildfires have stretched firefighting manpower and resources and spurred evacuations of homes and businesses.
Cal Fire Battalion Chief Jonathan Cox, who reported some injuries, said "this fire is explosive."
Gov. Brown on Monday issued an emergency proclamation for Napa, Sonoma and Yuba counties.
"These fires have destroyed structures and continue to threaten thousands of homes, necessitating the evacuation of thousands of residents," the proclamation said. "These fires have damaged and continue to threaten critical infrastructure and have forced the closure of major highways and local roads."
Citing strong winds and extreme weather conditions, the proclamation said the Tubbs Fire and the Atlas Fire began burning in Napa County and spread into Sonoma County, while other fires also sprouted up nearby.
Photos show a Kmart and a pizza restaurant destroyed in Santa Rosa.
Winds expected to ease
The National Weather Service in San Francisco on Sunday issued a "red flag warning" for the Bay Area because of current or impending critical fire weather conditions.
The warning cited dry, "windy locations through the Napa Valley and northern Sonoma County valleys." Gusts ranging from 35 mph to more than 60 mph were recorded. There were a few hurricane-force gusts of more than 74 mph.
"Any fires that develop will likely spread rapidly," the warning said.
Forecasters said winds will remain strong on Monday morning but are expected to ease by midday. But the warning will likely remain in effect because of the warm and dry conditions and the presence of wildfires.
Responders worked through the night to fight the fires. KPIX said the blazes had stretched local firefighting resources, and calls were out for assistance. Kaiser Permanente Hospital in Santa Rosa evacuated patients. News footage showed patients wheeled out on stretchers.
Santa Rosa also ordered evacuations in several neighborhoods. The Sonoma County Sheriff's Office said hotels were evacuated and shelters were set up. The county is working to set up shelters at fairgrounds to house animals. In Napa County, evacuations were underway as firefighters battled blazes.
There were also fires in other counties such as Lake and Mendecino.
Napa Mayor Jill Techel says authorities had to evacuate Montecito Boulevard and Monte Vista Avenue in the city. She estimates that about 100 homes have been evacuated. She warns that those trying to contact loved ones may experience spotty mobile phone coverage.
Napa's Biermann says authorities hope to have a better grasp on the extent of the fires now that the sun is up and firefighting aircraft can survey the area.
He was asked multiple times if it was suspicious that three fires began around the same time, he reiterated that the causes of all three fires are unknown.
"Fire has burned all the way through the Silverado Country Club area," Biermann said in a reference to the Silverado Resort and Spa.
Napa County Sheriff John Robertson says he hasn't had any issues with people refusing to evacuate: "Most of the people are leaving their homes. This is a big event."
Residents fleeing homes, hospitals
Veronica Ortega was at the Kaiser Permanente Hospital in Santa Rosa when she smelled smoke and saw flames through the window of her fiancé's room on the fourth floor.
The two soon were loaded onto a city bus and shuttled away.
Brian Alexander, a 34-year-old Santa Rosa resident, told CNN about stepping in to help his neighbors as the inferno surrounded his apartment complex.
He drove four neighbors to nearby shelters. As they fled the flames one of them told him, "There's no need to repent. Hell is already here."
"I couldn't live with myself if someone died or couldn't get help and I could have been there to stop it," said Alexander, who packed what he could into his car, eyeing his apartment one final time amid the ash and smoke that burned his eyes and made breathing difficult.
He later drove to Kaiser Permanente Hospital, where he works in environmental services, and began helping the hospital evacuate patients by moving gurney beds to the ambulances and city buses that were ferrying the patients to safety.
"In a situation like this, it is really important that we be the best we can be," he said. "There was no other option."
Alyssa O'Gorman and her family fled their home in the nick of time. As the flames closed in Sunday night, they left without a change of clothes. O'Gorman, her parents and her grandfather gathered their animals and were out of the house in minutes.
O'Gorman, a nursing assistant, was driving home from her job when she first spotted flames.
After evacuating the house, which sits at the dead end of a one-lane road in rural Napa County, she and her family watched from a distance as a propane tank exploded and their home's roof caught fire.
If O'Gorman hadn't been coming home from work to wake her family, "we would have been in the house trapped," she said.
Meanwhile, as she takes refuge with a relative in Santa Rosa, O'Gorman can't stop thinking about about the valuables and keepsakes left behind in her home, which she now believes is gone.
She's too distraught to sleep.
"I'm probably not going to," she says. "Not until I can see my house."
Along with Kaiser Permanente hospital, Sutter Hospital in Santa Rosa was also evacuated. Much of a mobile home park behind the Kaiser facility burned, CNN affiliate KPIX said.
In Santa Rosa, the Fountain Grove Inn and Hotel was destroyed and another hotel, the Hilton, was in flames, the affiliate reported.
The swath is known as wine country. KPIX reported flames near the Domaine Carneros winery.