Oct. 12 (UPI) -- Sonoma County Sheriff Robert Giordano said he expects the death toll in California's massive wildfires to increase Thursday as cadaver dogs began searching for hundreds of missing people.
He said more than 450 people were missing in the county and it would be "unrealistic" to think that some of them aren't dead.
"We've found bones that were almost completely intact," Giordano said of the recovery of remains. "We've found bodies that are nothing more than ashes and bones.
"We will do everything in our power to locate all the missing people. I promise you we will handle the remains with care and get them to their loved ones."
Winds of over 50 mph have spread 22 distinct wildfires in Northern California's wine country since Sunday. The death toll from the blazes increased to 29, including 15 people in Sonoma County, eight in Mendocino County, two in Napa County and four in Yuba County.
Giordano updated the roll Thursday afternoon, saying one body was discovered overnight.
The wildfires caused substantial damage in Napa and Sonoma counties -- including more than 3,500 structures destroyed.
Officials say they consider air quality in Northern California's Bay Area to be unhealthy and is expected to deteriorate in coming days due to multiple deadly wildfires.
The fires were spreading smoke and airborne particulate matter, leading to harmful breathing conditions.
San Francisco hospitals received patients in their emergency rooms complaining of respiratory issues likely related to the smoke, said Rachael Kagan, of the San Francisco Department of Health.
"We're going to see a really strong settling of the smoke in the Bay Area on Friday and Saturday," said National Weather Service's Bay Area office meteorologist Brian Garcia. "Not to mince words. It's going to be really bad."
"We're seeing the worst air quality ever recorded in many parts of the Bay Area. The entire Bay Area population is likely being affected by the smoke," Tom Flannigan, of the Bay Area Quality Air Management District, said. "Up in the Napa area and even up in San Rafael, basically all of the North Bay, is experiencing the highest readings we've ever observed."
The five highest readings on the Environmental Protection Agency's Air Quality Index in its 5 a.m. update Thursday were in the Bay Area. Napa leads the list with a reading of 244, regarded as very unhealthy. Truckee, Salinas, Santa Cruz and Atascadero, all affected by the wildfires, had readings between 151 and 158, regarded as unhealthy.
Schools across the Bay area are closed and more than 80 flights from San Francisco International Airport were canceled on Wednesday due to smoky conditions. Artifacts from the historic Spanish Mission in Sonoma have been removed for safekeeping.