The causes of the fires are unknown.
At least 8,000 firefighters and support personnel and 124 aircraft 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. Authorities said 1,000 fire departments from San Diego to Oregon were assisting.
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 285 people were missing in Sonoma County as of Wednesday evening, according to the sheriff's office. There have been 600 total missing reports since the fires began, but 315 have those have been located safe.
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."
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