THE EXPANDING RISKS OF EXTREME WILDFIRES

In the past decade, several regions across the globe have experienced devastating fire seasons with fire attributes unparalleled in the modern era. These extreme fires and fire seasons have resulted in far-reaching cascading impacts, including direct harm to communities, challenges in fire suppression efforts, high carbon emissions, and post-fire debris flows. Extreme fires are responsible for the vast majority of burned area as well as coupled societal-ecosystem losses from wildfire in recent decades, yet represent a small fraction of fire events. Warmer and drier fire seasons in regions with abundant fuel – in some cases a legacy of successful fire exclusion through management – have propelled recent increases in wildfire extremes in many parts of the western US among other areas globally. The wildfire crisis has further been compounded by long-term expansion of the wildland-urban interface in fire prone lands without appropriate adaptation to background risks. My talk aims to synthesize recent findings central to the risks of extreme wildfires and specifically the role of climate and weather in enabling and driving them. First, I will synthesize the top-down meteorological ingredients that have catalyzed such extremes across fuel- to flammability-limited fire regimes focused on the western US, and the degree to which human-caused climate change can be linked to the spectrum of drivers. Secondly, I will examine a subset of fire events associated with downslope wind events that have been linked to the most deadly fires in the western US and globally in recent decades. Finally, I will provide an updated analysis of projected changes in hydroclimate whiplash – the rapid shift from extreme drought to extreme wet conditions – as these swings are often implicated in post-fire debris flows.