The NWS has issued a "Particularly Dangerous Situation" Red Flag Warning for Southern California, effective until 10 a.m. Tuesday, with a fire weather watch continuing from Tuesday evening through Thursday evening due to powerful Santa Ana winds.

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.