Santa Ana winds will continue whipping through Southern California through Thursday, sparking fears that progress made fighting wildfires that have scorched over 40,000 acres and left 28 dead could be reversed and more blazes could break out.

Critical fire weather is expected to continue until Wednesday at the earliest, increasing the risk that fires will spread further.

As winds across the Southern California area are calmer than their peak and firefighters are making progress, the threat to the fire-weary region remains with Santa Ana winds expected to continue in the coming days.

"A Red Flag Warning means that critical fire weather conditions are either occurring now, or will shortly," the NWS said.