Two firefighters watch as a home burns in a wildfire in La Conchita, Calif., Dec. 7, 2017.
Two firefighters watch as a home burns in a wildfire in La Conchita, Calif., Dec. 7, 2017.

Thursday was the fourth day of devastating wildfires in Southern California, and a new blaze erupted north of San Diego and spread quickly.

Fire officials said Thursday evening a wildfire north of Los Angeles has destroyed 439 homes and buildings.

Officials say the region’s infamous Santa Ana winds have increased the four biggest fires, extending from Los Angeles up the Pacific Coast to Santa Barbara County.

In this image from video released by Chase Bonefan
In this image from video released by Chase Bonefant @ChaseBonenfant, shows the Lilac fire burning in Bonsall, Calif. A brush fire driven by gusty winds exploded rapidly Thursday north of San Diego, destroying dozens of trailer homes in a retirement community and killing race horses at an elite training facility.

The CAL Fire state agency said the hot dry winds from the California desert and the extremely low humidity conditions are expected to continue through Sunday.

“Let me be clear, no amount of resources can keep up with the predicted conditions,” CAL Fire Director Ken Pimlott said.

The state fire agency said on Twitter: “Prepare now to ensure if evacuated you and your family are ready to GO!”

With wind gusts of up to 145 kilometers per hour (90 mph) expected to continue through Friday afternoon, Los Angeles County Fire Chief Daryl Osby warned people to remain alert as he and other officials urged the public to evacuate at the first sign of danger.

The biggest fire is the Thomas Fire, about 90 kilometers northwest of the city of Los Angeles It has burned more than 47,000 hectares.

A fire Wednesday in the upscale Bel-Air neighborhood of Los Angeles temporarily shut down several highways and the Getty Center art complex was closed to protect the art collection from smoke damage.

A fire in 1961 burned 500 homes in the tony neighborhood, some belonging to Hollywood stars.

Several hundred Los Angeles schools were closed Thursday.

A fire north of San Diego expanded in just a few hours Thursday from 4 hectares to 1,012 hectares.

Fires are not uncommon in Southern California this time of year before the winter rains set in, when the vegetation is tinder dry and winds blast the region.

This year has been a particularly bad year for California fires. Just weeks ago, wildfires broke out in Northern California, killing 44 people and destroying 8,900 homes and other buildings.

California Department of Forestry and Fire Protection said Tuesday wildfires have burned more than 400,000 hectares so far this year. The data does not take into account the fires currently burning.