Wildfires rip through California communities

Wind-driven fires tore through California communities Tuesday for the second time in two months, leaving hundreds of homes feared lost and uprooting tens of thousands of people.

The most damaging fire was in Ventura County northwest of Los Angeles, where 150 structures were confirmed destroyed. But a fire official said he suspected "hundreds more" would be lost when flames died down enough to make a thorough assessment.

In the San Gabriel Mountains foothills of Los Angeles about 72 kilometres away from the city, 30 structures burned. Mayor Eric Garcetti said the gusty winds expected to last most of the week had created a dangerous situation and he urged 150,000 people under mandatory evacuation orders to leave their homes before it's too late.

"We have lost structures, we have not lost lives," he said. "Do not wait. Leave your homes."

The fires in Ventura County lit up hillsides and spread rapidly Monday evening from rural rolling hills to dense subdivisions. Residents, already warned of extreme fire danger, were sent automated phone alerts and evacuations appeared to proceed smoothly.

As the sun rose on Tuesday, the first of at least three additional Southern California fires broke out, fuelled by stiff winds that prevented firefighting aircraft most of the day from dumping water to protect homes or attack the march of flames.

In addition to prompting hasty evacuations, the fires shut down two freeways for hours and sent heavy, acrid smoke billowing over the Los Angeles area, creating a health hazard for millions.

There were no immediate reports of any deaths. Two people were critically injured in a small San Bernardino County fire, but no other serious injuries were reported. The fires were under investigation and no causes had been found.

The Ventura wildfire exploded to nearly 207 sq km in a matter of hours. It was fanned by dry Santa Ana winds clocked at well over 96kph and spit embers nearly 1km ahead of fire lines.

Lisa Kermode ignored the first evacuation alert that buzzed on her phone when it said the fire was 15 miles (24 kilometers) away from her home. But the flames were nearly on top of her an hour later when she rounded up her three children, still in their pajamas, and told them to grab some jeans so they could leave.

They returned home Tuesday to find their home and world in ashes, including a Christmas tree and the presents they had just bought.

"We got knots in our stomach coming back up here," Kermode said. "We lost everything, everything, all our clothes, anything that was important to us. All our family heirlooms — it's not sort of gone, it's completely gone."

The fires came just eight weeks after the deadliest and most destructive series of wildfires in state history burned through Northern California and its fabled wine country and killed 44 people dead and destroyed 8,900 homes and other buildings.

Fires are not typical in Southern California this time of year but can break out when dry vegetation and too little rain combine with the Santa Ana winds. Hardly any measurable rain has fallen in the region over the past six months.