Mega Forest Fires Intensify Flood Magnitudes in Southeast Australia

Recent forest fires potentially intensify flood hazards. However, fire amplification of floods is not well understood at a large scale due to the complex compound impacts and climate variability, while available small-scale cases may represent regional changes. Here, we show that 2019–2020 mega in southeast Australia, with unprecedented burned areas, significantly (p < 0.05) increased peak discharges during 2 years after fires. Spatially, on these are much stronger regions winter-dominated uniform rainfall but insignificant summer-dominated rainfall. The divergence reveals areas can aggravate by exacerbating infiltration-excess runoff processes exert significant effects where saturation-excess dominate. People be increasingly exposed such hazards, especially have become more frequent under change.