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Compound Extremes Drive The Western Oregon Wildfires Of September 2020, John T. Abatzoglou, David E. Rupp, Larry W. O'Neill, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

Several very large high‐impact fires burned nearly 4,000 km² of mesic forests in western Oregon during September 7–9, 2020. While infrequent, very large high‐severity fires have occurred historically in western Oregon, the extreme nature of this event warrants analyses of climate and meteorological drivers. A strong blocking pattern led to an intrusion of dry air and strong downslope east winds in the Oregon Cascades following a warm‐dry 60‐day period that promoted widespread fuel flammability. Viewed independently, both the downslope east winds and fuel dryness were extreme, but not unprecedented. However, the concurrence of these drivers resulted in compound extremes …