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.

We've seen reports about Los Angeles County being under "fire weather watch" and "red flag warning." What is the difference?

That’s leading to the creation of mountain waves, which arise when strong winds blow perpendicular to a mountain range. The waves shoot down the coastal side of the mountains, gaining speed along the way, and are more casually referred to as simple Santa Ana winds.

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

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

A new round of high winds could whip up more fires in the L.A. area, with a Red Flag warning in effect through Wednesday.