Theses and Dissertations Collection

Red Flag Warnings (RFWs) issued by the National Weather Service in the United States (U.S.) are an important fire early warning system based on forecasts of critical fire weather that foster fire activity including the occurrence of large fires. However, verification of RFWs as they relate to fire activity is lacking, thereby limiting means to improve forecasts as well as increase value for end-users. We evaluated the efficacy of RFWs as forecasts of large fire occurrence for the Northwestern U.S and found favorable performance broadly across the area, along with substantial skill and improvement over reference forecasts. We further demonstrate that the skill of RFWs is significantly higher for lightning-ignited large fires and for forecasts issued during periods of high fuel dryness. The results of this first verification study of RFWs lay the groundwork for future efforts towards improving the relevance and usefulness of RFWs to better serve the fire community and public.