Understanding Fire Danger and Red Flag Warnings
Fire danger ratings and Red Flag Warnings are critical tools used to assess and communicate wildfire risks. Fire danger is a daily composite index that evaluates factors such as vegetative fuel moisture, landscape drought, and weather conditions across a Fire Danger Rating Area (FDRA). It is expressed in five adjective ratings: Low, Moderate, High, Very High, and Extreme. In contrast, a Red Flag Warning is issued by the National Weather Service when specific atmospheric conditions, such as low relative humidity (≤15%) and high sustained winds (≥25 mph), are expected within 12 to 48 hours. These warnings indicate an increased likelihood of extreme fire spread. Both tools are essential for wildfire management, resource allocation, and public safety measures [CASRAI, 2026].