By Marcus Wohlsen 
The Associated Press
Copyright 2008 The Associated Press

SAN FRANCISCO — Hundreds of wildfires sparked by lightning flared Sunday across the heart of wine country and remote forests in Northern California, the latest batch of destructive blazes in the bone-dry state.

One had spread across nearly 6 square miles by early Sunday after starting the previous afternoon in Napa County and quickly moving into a mostly rural area of Solano County.

The fire threatened more than 100 buildings as it fed on grassy woodland about 40 miles southwest of Sacramento, said Roger Archey, a spokesman for the California Department of Forestry and Fire Protection, or Cal Fire.

It was 35 percent contained Sunday evening and had destroyed one home, officials said. Evacuations were ordered for some residents, said agency spokeswoman Nancy Carniglia.

Wildfires have destroyed more than 175 homes in Northern California so far this year. Blazes started popping up in the region just as California's unofficial fire season began in mid-May, following the state's driest two-month period on record.

Two small blazes about 25 miles south of San Jose forced several residents from their homes Sunday. Both were partially contained, and officials said most residents would be let back into their homes by Monday. Those fires were also blamed on lightning.

Thunderstorms were responsible for as many as 75 fires in Shasta-Trinity National Forest, about 160 miles north of Sacramento. They ranged in size from less than an acre to more than a square mile. None immediately threatened homes, said Forest Service spokesman Michael Odle.

Mendocino County had as many as 90 fires, charring nearly 8 square miles, Cal Fire officials said.

South of San Francisco, a fire that started Friday in Santa Cruz County and destroyed homes and closed a stretch of highway was contained after charring just less than a square mile. Evacuation orders were lifted Saturday, a day after roughly 2,000 people fled their homes.

It was the third major blaze to hit Santa Cruz County in the past month. A 520-acre blaze destroyed 11 buildings in the Santa Cruz Mountains, and a fire near Corralitos covered more than 4,200 acres and destroyed about 100 buildings.

Along the coast in the Los Padres National Forest, a wildfire burning since Saturday forced 75 homes and businesses to be evacuated. And just miles away, firefighters worked to stanch a huge fire that has destroyed two homes since it began two weeks ago. It was nearly 60 percent contained after charring 83 square miles.

Near the Nevada border, authorities said Sunday that they are studying a "person of interest" in last summer's catastrophic Lake Tahoe wildfire but lack enough evidence to make an arrest.

Tuesday will mark the one-year anniversary of the blaze, which destroyed 254 homes, caused $140 million in property damage and scorched nearly 5 square miles. Investigators think the fire started with stray embers from an illegal campfire at a popular party spot.

In southern New Mexico, firefighters burned out vegetation along a forest road to stop a 67-square-mile wildfire that's destroying grazing allotments. The fire 20 miles southwest of Hope was 35 percent contained Sunday, fire information officer Deanna Younger said.

An air tanker and helicopters were dropping water and retardant on the fire, she said.

Two other lightning-sparked wildfires also had burned nearly 47 square miles. One was west of Roswell in southern New Mexico and the other west of Raton in the northern part of the state.

The fires were feeding on grass, brush, cacti and some pinon pine and juniper trees. No structures were threatened.

Associated Press writer Heather Clark contributed to this report.