Defining Extreme Wildfire Events: Difficulties, Challenges, and Impacts

TLDR

Every year, extraordinary wildfires overwhelm suppression efforts, cause extensive damage and fatalities, and their increasing frequency has sparked debate but no consensus on terminology, prompting the emergence of the extreme wildfire event (EWE) concept whose definition remains unclear. This paper aims to construct a holistic, transdisciplinary definition of EWE as a social‑ecological phenomenon. Using a literature review and transdisciplinary approach, the authors propose a seven‑category wildfire classification based on spread, behavior, and suppression difficulty, defining categories 5–7 as extreme wildfire events.

Abstract

Every year worldwide some extraordinary wildfires occur, overwhelming suppression capabilities, causing substantial damages, and often resulting in fatalities. Given their increasing frequency, there is a debate about how to address these wildfires with significant social impacts, but there is no agreement upon terminology to describe them. The concept of extreme wildfire event (EWE) has emerged to bring some coherence on this kind of events. It is increasingly used, often as a synonym of other terms related to wildfires of high intensity and size, but its definition remains elusive. The goal of this paper is to go beyond drawing on distinct disciplinary perspectives to develop a holistic view of EWE as a social-ecological phenomenon. Based on literature review and using a transdisciplinary approach, this paper proposes a definition of EWE as a process and an outcome. Considering the lack of a consistent “scale of gravity” to leverage extreme wildfire events such as in natural hazards (e.g., tornados, hurricanes and earthquakes) we present a proposal of wildfire classification with seven categories based on measurable fire spread and behavior parameters and suppression difficulty. The categories 5 to 7 are labeled as EWE.