On Wednesday, Jan. 22, the Hughes fire broke out in Castaic amidst the red flag warning, spreading to over 9,000 acres by Wednesday evening as dry and windy weather affected the area.

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.