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.

Santa Ana winds are whipping Southern California on Tuesday, sparking fresh fears that progress made fighting wildfires that have scorched over 40,000 acres and left 27 dead could be reversed and more blazes could break out.

The NWS Los Angeles/Oxnard CA issued a wind advisory at 12:54 a.m. on Wednesday valid for Wednesday between 2 p.m. and 10 p.m. The advisory is for Southern Ventura County Mountains, Interstate 5 Corridor and Eastern San Gabriel Mountains.