Exploring a simple fire weather index in the Pacific Northwest

There is no shortage of fire indices designed to capture the influence of weather conditions on fire behavior or fire danger – weather is inherent in the component indices of the United States' National Fire Danger Rating System, the Canadian Forest Fire Danger Rating System, the McArthur Fire Indices, the Behave family of fire behavior tools, PROMETHEUS, the Haines Index, the Fosberg Fire Weather Index, the Nesterov Index, and more. Most of these are fuel-centered indices, using weather conditions primarily to determine the state of one or more fuel types, models, or classes. Even with all of these indices, research scientists continue to search for a better index, often resorting to more and more complex formulations. This presentation examines yet another index, but one that seeks to revert to a simpler structure and does not place weather at the service of fuels. Several variants of this simple fire index are mapped over the Pacific Northwest, and the presentation focuses on horizontal and vertical patterns, diurnal cycles, and behavior during fire events in the region.