FRESNO — California's raging wildfires have created a smoky haze so stifling that doctors in the state's landlocked farm country say their waiting rooms have been crowding with patients struggling to breathe amid the soot-laden air.
Even without the blazes, the farming towns and subdivisions dotting the long, flat San Joaquin Valley are typically shrouded in a layer of smog during the summer.
But airborne ash from the hundreds of lightning-sparked fires caused such a spike in air pollution over the weekend that meteorologist Shawn Ferreria said it took his breath away.
"I went and bought a mask because my lungs were not happy with me," said Ferreria, a senior air quality specialist for the San Joaquin Valley Air Pollution Control District. "What we are experiencing is way out of historical norms. I thought if I'm going to continue riding my bike to work, I better take an extra measure."
Hundreds battling blazes
Hundreds of firefighters were working overtime Tuesday to beat back blazes burning from the western edge of the Sierra Nevada to coastal mountains near Big Sur, where authorities enforced new, mandatory evacuations along a roughly 15-mile stretch of Highway 1.
Gov. Arnold Schwarzenegger deployed 200 National Guard troops to fire lines Tuesday to relieve weary crews, U.S. Forest Service officials said.
"I can't say enough about the brave men and women working tirelessly, and with little rest, to battle the blazes across California," Schwarzenegger said of the current crews. "I am announcing a big shot in the arm to their efforts by ordering California National Guard soldiers to provide direct ground support on the fires."
Some 1,200 homes are threatened by the Big Sur fire, which has destroyed 17 homes while burning 74 square miles by Tuesday morning. It was just 3 percent contained and parts of it were just a few miles south of Big Sur.
Some 200 residents along an 18-mile stretch of Pacific Coast Highway 1 from Big Sur to the south are under a mandatory evacuation order starting at 5 p.m.
Officials had hoped a fog bank along the Northern California coast would aid firefighting efforts, but the moisture did not extend inland, said Brian Tentinger, a meteorologist with the National Weather Service in Monterey.
Even as crews made headway against some of the worst blazes, air district officials in the Central Valley grew concerned that wind patterns would send more smoke billowing into the valley, which is bordered on three sides by mountains.
Once the tiny particles of soot — which are blamed for causing asthma and other respiratory problems — reach the valley, they're sealed in under a layer of warm air created by hot summer temperatures.
"Our waiting rooms are full of people with sore throats, itchy eyes and sniffles," said Kevin Hamilton, a respiratory therapist with Sequoia Community Health Center in Fresno. "It's certainly driving the clinic's appointments up."
Pollution levels returning to normal
In the Bay Area, a thin haze blanketed skyscrapers in downtown San Francisco, but local officials said pollution levels had finally returned to normal levels.
In the Big Sur region of the Los Padres National Forest, about 200 people were ordered to evacuate Tuesday, and evacuation orders remained in place for occupants of at least 75 homes who were forced to leave the region last week.
Endangered condors also sought to avoid the thick smoke by hunkering in cliffs along the Pacific Ocean.
At Tassajara Zen Mountain Training Center monastery in nearby Carmel Valley, students and volunteers stretched sprinklers atop buildings in case embers started falling.
"Air quality is the wrong word. There is no quality," said Chris Slymon, who monitors the monastery's closest phone from a crossroads at Jamesburg 10 miles away.
In the Sequoia National Forest east of Bakersfield, crews from as far away as Kansas struggled to contain the 8,200-acre Piute Fire. Powerful gusts and choking smoke traveling up the steep canyons hampered their progress, and residents of neighboring towns were ordered to evacuate.
Officials in Mariposa, about 70 miles northwest of Fresno, canceled the town's annual fireworks show at the county fairgrounds because firefighters were using it as a staging area to contain a blaze that has burned through more than 2,700 acres, county officials said.
'Eat it one bite at a time'
The surprising number of fires has forced firefighters to allocate their resources carefully: they focus on communities in the path of flames, allowing other blazes to chew through unpopulated forest land.
Video: Fire fatigue "It's like eating an elephant — you've got to eat it one bite at a time," said Jason Kirchner, a spokesman for the U.S. Forest Service. "We have to take a step back, figure out where the best place is to make a stand and sometimes wait for the fire to come to us in those situations."
This year is extraordinary for the number of active fires, Kirchner said. The weekend of June 21 had 1,200 fires — a number Forest Service officials said appeared to be an all-time record in California.
Many of the current fires could take weeks, or months, to extinguish.
Long-running wildfires are not unusual in California. It was four months before firefighters controlled a blaze that blackened more than 240,000 acres of Santa Barbara County backcountry last year.
Kirchner said wildfires have not been blamed for any significant injuries to civilians or firefighters even though some 570 square miles of land have burned in California this season. There were a few minor injuries among firefighters working on the Shasta-Trinity fire.
"It is extremely steep, very rugged territory, and there are a lot of injuries, twisting ankles, slipping on hills," Kirchner said. Burning debris is "rolling downhill right past your containment line. It's very complicated, difficult, dirty firefighting work."
The Associated Press contributed to this report.