Southern California is braced for "extremely critical fire conditions" caused by a new period of Santa Ana winds today through tomorrow across parts of Los Angeles and Ventura counties as the battle to contain raging blazes goes on.

With the strongest gusts expected on Tuesday, extreme fire condition threats will prevail until midweek, L.A.-area fire chiefs say.

With the two largest wildfires in Los Angeles County still mostly uncontained, the winds which drove their explosive growth have whipped up once again.