Southern California wildfire prompts evacuation order for thousands

A wildfire fuelled by gusty Santa Ana winds ripped through rural land southeast of Los Angeles on Monday, forcing about 4,000 people from their homes, fire authorities said.

The so-called Highland Fire erupted at about 12:45 p.m. in dry, brushy hills near the unincorporated Riverside County hamlet of Aguanga.

As of late Monday night, it had spread over about 5 square kilometres of land, fire spokesman Jeff LaRusso said.

About 1,300 homes and 4,000 residents were under evacuation orders, he said.

The fire had destroyed three buildings and damaged six others but it wasn't clear whether any were homes. The region is sparsely populated but there are horse ranches and a large mobile home site, LaRusso said.

No injuries were reported.

Winds of 32 to 40 kph with some higher gusts drove the flames and embers through grass and brush that were dried out by recent winds and low humidity so that it was "almost like kindling" for the blaze, LaRusso said.

The winds were expected to ease somewhat overnight and fire crews would attempt to box in the blaze, LaRusso said.

But, he added: Wind trumps everything. Hopefully the forecast holds.

A large air tanker, bulldozers and other resources were called in to fight the fire, one of the few large and active blazes to have erupted so far in California's year-round fire season, LaRusso said.

Southern California was seeing its first significant Santa Ana wind condition. The strong, hot, dry, dust-bearing winds typically descend to the Pacific Coast from inland desert regions during the fall. They have fuelled some of the largest and most damaging fires in recent California history.

The National Weather Service said Riverside County could see winds of 24 to 40 kph through Tuesday with gusts as high as 64 kph. The weather service issued a red flag warning of extreme fire danger through Tuesday afternoon for parts of Los Angeles and Riverside counties.