LOS ANGELES -- Thousands of Californians were allowed to return to their homes Wednesday as calmer winds helped firefighters beat back two wind-driven wildfires that had spurred widespread evacuations.

Roughly 100,000 people were ordered to evacuate Monday after the wildfires broke out in brushy hills above cities in Southern California's Orange County amid fierce winds and extremely dry weather conditions.

On Wednesday, evacuation orders were lifted for all residents in the city of Irvine about 35 miles (56 kilometres) south of Los Angeles, which saw more than a quarter of its 280,000 people forced from their homes. Evacuation orders also were lifted for the nearby Blue Ridge Fire, where thousands of people in Yorba Linda and neighbouring communities had been under orders to flee.

Firefighters made progress as the winds subsided and the spread of the flames slowed. The Irvine-area Silverado Fire was 32% contained by Wednesday evening and the Blue Ridge Fire to the north was 23% surrounded after being virtually uncontained a day earler.

"With favourable weather, fire crews will find opportunities to establish more control lines," the California Department of Forestry and Fire Protection, or Cal Fire, said in a statement.

The Silverado Fire burned 21 square miles (54 square kilometres). No homes were lost but two firefighters remained hospitalized after suffering second- and third-degree burns over large areas of their bodies, Orange County Fire Authority Chief Brian Fennessy said.

The Blue Ridge Fire, at 22.4 square miles (58 square kilometres), destroyed one structure and damaged seven.

Two firefighters who battled the Silverado Fire were hospitalized after suffering second- and third-degree burns, Fennessy said.

Scientists have said climate change has made California much drier, meaning trees and other plants are more flammable. October and November are traditionally the worst months for fires, but already this year 8,600 wildfires in the state have scorched a record 6,400 square miles (16,600 square kilometres) and destroyed about 9,200 homes, businesses and other buildings. There have been 32 deaths.

The fierce winds subsided Tuesday night and calmer breezes were expected the rest of the week, but continued warm and dry weather that make for potentially dangerous wildfire conditions were forecast into November, with no rain.

The cause of the Silverado Fire is under investigation, state fire officials said.

The Southern California Edison utility reported to state officials that it was investigating whether its equipment might have sparked the blaze. According to Edison's report to utility regulators, a "lashing wire" that ties a telecommunications line to a supporting cable may have come into contact with a separate 12,000-volt conductor line above it.

Facing extreme wildfire conditions this week including hurricane-level winds, Pacific Gas & Electric Co. in Northern California preventatively cut power to nearly 1 million people and avoided major wildfires during its outage.

Edison defended its decision not to institute a blackout in that particular area. Spokesman Chris Abel said wind speeds in the mountains above the city of Irvine on Monday morning did not initially reach the threshold to cut power, though they did later in the morning and some electric circuits were cut.

By late Wednesday, power had been restored to Edison's customers who had experienced planned outages, according to the utility. In Northern California, power had been restored to nearly all residents, according to PG&E.

On Wednesday, authorities in Northern California said a man injured last month in a blaze in Butte County died of his injuries.

Win Naing, 54, of Berry Creek, was burned in the fire but was able to drive from his home and find a firefighter who took him to a hospital. Naing died Oct. 21 at the UC Davis Medical Center, raising the total people who died in that blaze to 16, the Butte County Sheriff's Department said in a statement Wednesday.

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Taxin reported from Orange County. Associated Press reporters Brian Melley and Stefanie Dazio in Los Angeles and Olga R. Rodriguez in San Francisco contributed.