The most destructive wildfires in Los Angeles history Thursday have burned more than 54 square miles of land, destroyed thousands of structures and killed at least five people.

Red flag criteria is generally when relative humidity is at 15% or less, combined with sustained winds and/or gusts of 25 mph or greater. Both of these conditions must occur simultaneously for at least 3 hours in a 12 hour period, according to the NWS.

Red flag weather warning: A National Weather Service alert that warns the public — especially fire officials and firefighters — that strong winds are expected in specific areas of Southern California, and that there will be potentially dangerous fire weather conditions within the next 12 to 24 hours.

A red flag warning is in effect for parts of Santa Barbara County from 4 a.m. Tuesday to 6 p.m. Wednesday due to the forecast of strong winds, low

Another round of Santa Ana winds has moved into Southern California and will spread south through San Diego County late Thursday. The additional dry air also is expected to worsen the region’s already very low humidity levels,

A short reprieve in the strong destructive winds has granted firefighters an opportunity to curb the spread of the deadly Eaton Fire near Pasadena.

Another round of Santa Ana winds is forecast to sweep into SoCal on Thursday night into Friday morning, putting most of the region under a critical fire risk, as emergency responders battle to contain quickly spreading wildfires.

The National Weather Service on Wednesday extended the wildfire warning through the end of the week for much of East County.

ABC 10News reporter Moses Small reported live from Alpine, where wind gusts could reach 75 miles per hour in the next couple of days, elevating the fire risk for San Diego County.

In San Diego, the Red Flag Warning for inland and mountain communities has been extended until at least 6 p.m. Friday, so our county remains on high alert due to the elevated fire risk. ABC 10News is bringing you extensive coverage on both the Los Angeles fires and how our area is preparing for the worst in this edition of the Wake Up Call newsletter.