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.

Millions of California residents were placed under a red flag warning through Thursday amid threats of further fires with looming winds in the forecast, according to multiple reports.

Dangerous Santa Ana winds are expected to return to the Los Angeles area this week, potentially fueling the growth of new and existing wildfires, according to FOX Weather.