OJAI, United States (AFP)— Brutal winds that fuelled southern California’s firestorm finally began to ease Saturday, giving residents and fire fighters hope for respite as the destructive toll of multiple blazes came into focus.

After a five-day siege, some Californians were finally able to return home to inspect the damage wrought by the wildfires, which forced hundreds of thousands of people to flee and destroyed some 700 structures including multimillion dollar mansions.

Despite the intensity of the fires that raged on six different fronts — stretching from areas north of Los Angeles down to the San Diego region — authorities have reported only one fatality. With gusts of up to 60 miles per hour (95 kilometres per hour), the relentless seasonal Santa Ana winds had continued to stoke the fire Friday, spitting embers and creating “extreme fire danger.” “There’s still tons and tons of hot spots out there,” Cal Fire Captani Jon Heggie said early Saturday.

A “red flag” warning issued by the National Weather Service is in effect until 8 p.m. Sunday. The strongest winds are expected in the San Diego County mountains and foothills, with gusts over 60 mph, the NWS predicted.

Winds were expected to calm somewhat but a red alert was extended into Sunday due to expected low humidity.

And despite the easing of the gusty Santa Anas, meteorologists warned that smoke and ash could linger, prompting several counties to maintain air-quality warnings.

In the mountain town of Ojai the air-quality index was hovering over 500 — at the top of the “hazardous” scale — as fumes from the “Thomas” fire hung trapped by the mountains.

Since erupting in Ventura County late Monday, that blaze has seared 148,000 acres (60,000 hectares), but an area fire department spokesperson said Saturday containment should improve “after aggressive fire fighting” the day prior.

The material cost of fire suppression efforts has skyrocketed to some $17 million, Ventura officials estimated.

The “Skirball” fire — near the affluent, star-studded Bel Air district — was at least 50 per cent contained after engulfing entire hillsides in flames.

Fire fighters contained 80 per cent of the “Creek” fire— the largest blaze that menaced the LA region, which roared through more than 15,000 acres — while the nearby “Rye” fire was some 65 per cent under control.

California’s state fire agency said “favourable conditions helped make considerable progress today” but warned that “residents should remain vigilant as conditions can change quickly.” Authorities near San Diego — where the “Lilac” fire had rapidly charred more than 4,000 acres after igniting Thursday morning — issued a similar notice, saying improvement was expected but urging residents to remain on high alert.

Four civilians and two firefighters were injured in that blaze, which also claimed the lives of more than two dozen racehorses after tearing through eight barns.

In Fallbrook, in northern San Diego County, houses were destroyed and ravaged trees lay horizontal.

US President Donald Trump has issued a state of emergency in California, authorising the release of federal funds.

The week’s infernos capped California’s deadliest year ever for wildfires. More than 40 people died in October when fires swept through the state’s wine-producing counties north of San Francisco.