Los Angeles - The dreaded Santa Ana winds, which fan dangerous wildfires every autumn in southern California, roared through an area east of Los Angeles Monday burning over 1,500 hectares and forcing the closure of three major freeways.

The Marek fire was the first major blaze of the autumn season, which is traditionally the most dangerous wildfire period in the region. Thousands of firefighters had been placed on alert in the area, and backed by dozens of fire-fighting aircraft succeeded in getting the blaze 20 per cent contained. Nevertheless the blaze has forced 1,200 residents to evacuate.

Numerous structures were destroyed when the fire spread overnight, including a mobile home park and various industrial complexes that spewed thick black smoke over the city of San Fernando, said Los Angeles County Fire Inspector Ron Haralson.

Winds in the area were blowing at some 70 kilometres per hour, making the behaviour of the fire tough to predict.

"The winds could stir up hot spots and stir up this fire," Haralson said.