Los Angeles: Hundreds of structures are threatened by a fast-moving wildfire that has scorched over 82,000 acres (about 332 square km) in less than five days in Central California, authorities said. 

The wildfire, dubbed the Gifford Fire, broke out Friday afternoon when four separate ignitions along a California highway merged into a single wildfire currently burning on the Santa Lucia Road in both San Luis Obispo and Santa Barbara counties, according to the US Forest Service and the California Department of Forestry and Fire Protection.

Authorities said that the blaze is threatening more than 870 structures and was only 7 per cent contained as of Tuesday morning, Xinhua news agency reported.

The fire has prompted evacuation orders for residents in Santa Barbara and San Luis Obispo.

"Due to erratic fire behavior, residents should watch for changing conditions in their area," US Forest Service officials warned in an incident update.

As the warming and drying trend in the area is expected to continue from Wednesday through the weekend, firefighters will continue to construct contingency lines on the north and south flanks, authorities added.

There are more than 1,900 personnel assigned to the fire, alongside 40 hand crews, 115 engines, 23 dozers and 30 water tenders supported by air tankers and helicopters, according to InciWeb, a US interagency all-risk incident information management system.

The blaze is burning through steep terrain and creating a huge smoke column, said Capt. Scott Safechuck, a spokesperson with the Santa Barbara County Fire Department.

"A lot of it's in really inaccessible areas where even bulldozers can't even get into," Safechuck said, adding that aircraft are being added to the firefight.

The smoke will affect parts of Southwest California, the National Weather Service's Los Angeles office said, noting that wildfire smoke is a health risk. Smoke was expected to move toward the south and east. (IANS)