By Alex Dobuzinskis
(Reuters) - Hundreds of people forced to flee California's fiercest wildfire were allowed to return home on Friday, with firefighters gaining greater control over the blaze even as lightning strikes threatened to spark other fires in the drought-parched state.
Meanwhile President Barack Obama, at a bill-signing ceremony, remarked on the increased danger from wildfires due to climate change. Drought conditions have stoked extraordinary wildfire activity in the U.S. West this summer.
North of Napa Valley wine country, firefighters this week have made steady progress in the battle against the so-called Rocky Fire, which has destroyed 96 homes and outbuildings to rank as California's most intense ongoing blaze.
The fire spans parts of three counties in the rural ranch lands some 110 miles (177 km) north of San Francisco.
About 800 people were allowed on Friday to return to homes in areas that were threatened or scorched by the blaze, which has burned about 70,000 acres (28,328 hectares) and is 45 percent contained, said Daniel Berlant, a spokesman for the California Department of Forestry and Fire Protection.
"We've been making very good progress over the last several days," Berlant said.
Earlier this week, more than 13,000 people were under evacuation orders or advisories in the fire zone, but hundreds of those residents were allowed home on Thursday.
Berlant said he did not have an estimate of how many people remained evacuated on Friday.
Thunderstorms descended on the Sierra Nevada mountain range on Thursday in central California and areas further to the west and north, leading to a red flag warning for increased wildfire risk that would last through Friday evening, Berlant said.
Thousands of lightning strikes hit earth, but none sparked a major wildfire, he said.
California Governor Jerry Brown, a Democrat, has said climate change contributes to the state's wildfire problems, a theme Obama took up on Friday as he noted a "consistent escalation of the severity and the length of wildfire season."
"And a lot of that is attributable to the fact that climate change is going to be raising temperatures and creating less water, more vulnerability to a lot of forests out there," Obama said.
In Oregon, firefighters used four-lane Interstate 84 as a firebreak on Thursday to prevent the Lime Hill Fire in the eastern part of the state from reaching the nearby town of Huntington, U.S. Bureau of Land Management spokesman Larry Moore said.
(Reporting by Alex Dobuzinskis in Los Angeles; Additional reporting by Courtney Sherwood in Portland, Oregon; Editing by Dan Whitcomb and Eric Walsh)