Streamflow Flash Droughts and the Highly Responsive Behaviour of Streamflows to Drying

This study demonstrates the existence of streamflow flash droughts in 148 perennial catchments that represent an array of climatic zones from the tropics to mid-latitudes. Using Australia as a case study region, we show evidence of large losses in streamflow volumes within 5–15 days of flash drought onset. On average, at-risk catchments can experience nearly a 60% reduction in flow during the drought onset period. Rapid and large deficits are agnostic to catchment location, catchment physical characteristics, mean flow volume and antecedent streamflow conditions, though water-limited catchments tend to experience greater absolute reductions in flow than neutral and energy-limited catchments. The identification of streamflow flash droughts across such varied catchment types and locations suggests streamflow flash droughts are a potential risk globally.