A Red Flag Warning is a forecast warning issued to inform area firefighting and land management agencies that conditions are ideal for wild land fire ignition and propagation. After very dry or drought conditions, and when humidity is very low and especially when high or erratic winds which may include lightning are a factor, the Red Flag Warning becomes a critical statement for firefighting agencies, which often alter their staffing and equipment resources dramatically to accommodate the forecast risk. To the public, a Red Flag Warning means high fire danger with increased probability of a quickly spreading vegetation fire in the area within 24 hours.
The weather criteria for fire weather watches and red flag warnings varies with each Weather Service Office’s warning area based on the local vegetation type, topography and distance from major water sources but usually includes the daily vegetation moisture content calculations, expected afternoon high temperature, afternoon minimum relative humidity and daytime wind speed.
Outdoor burning bans may also be proclaimed by local law and fire agencies based on Red Flag Warnings.
