Firefighters from neighboring states arrived in California to help Monday after an "unprecedented" lightning storm sparked more than 800 wildfires, from Big Sur to wine country to Humboldt County. Thousands of firefighters battled the blazes on the ground and from the air and Gov. Arnold Schwarzenegger said he was alarmed by the number of fires that kept erupting. He said he was told late Sunday evening that the state had 520 fires, and he found it "quite shocking" that by morning the number had risen above 700. Moments later, atop state fire official standing at Schwarzenegger's side offered a grim update: The figure was actually 842 fires, said Del Walters, assistant regional chief of the California Department of Forestry and Fire Protection. All but a couple were in the northern part of the state. "This is an unprecedented lightning storm in California, that it lasted as long as it did, 5,000 to 6,000 lightning strikes," Walters said. "We are finding fires all the time." The assistance, mostly firefighting aircraft, arrived Monday from Nevada and Oregon after being requested over the weekend. Schwarzenegger said he had enlisted the help "because you can never prepare for 500 or 700 or 800 fires all at the same time." Part of the reason for the swelling number of wildfires was that local and state officials were still counting after the fierce thunderstorm Friday night that touched off the blazes. "We didn't get real lucky with this lighting storm," Walters said. "It wasn't predicted - which often happens with these storms that come in off the Pacific, there's no history of the weather as it approaches the shore - and so we got hammered." In Mendocino County alone there were 110 fires, with just 17 contained. Two of the biggest fires had each charred nearly 15 1/2 square kilometers. One started in Napa County and quickly moved into Solano County, and threatened about 250 homes about 40 miles (64 kilometers) southwest of Sacramento, said Kevin Colburn, a spokesman for the California Department of Forestry and Fire Protection. It was 60 percent contained Monday. The other was in the Shasta-Trinity National Forest, about 257 kilometers north of Sacramento, and threatened about 1,200 homes. Along the coast in the Los Padres National Forest, a 2,000-acre (809-hectare) wildfire burning south of Big Sur since Saturday forced the evacuations of 75 homes and businesses, destroyed one house and threatened hundreds of others. It also led to an emergency airlift Sunday of eight endangered California condors. U.S. Coast Guard helicopters transported the seven juveniles and one adult bird from a wildlife center to the Monterey Airport. A second fire in the Los Padres burned more than 57,000 acres (23,067 hectares) and has injured nine firefighters. In southern Arizona, two new human-caused wildfires were burning Monday but not threatening homes. A 700-acre (283-hectare) fire in the Rincon Mountains east of Tucson was fully contained. Lightning sparked that fire.