Diagnostic Classification of Flash Drought Events Reveals Distinct Classes of Forcings and Impacts

Abstract Recent years have seen growing appreciation that rapidly intensifying flash droughts are significant climate hazards with major economic and ecological impacts. This has motivated efforts to inventory, monitor, forecast drought events. Here we consider the question of whether term “flash drought” comprises multiple distinct classes event, which would imply understanding forecasting might require more than one framework. To do this, first extend evaluate a soil moisture volatility–based definition introduced in previous work use it inventory onset dates severity across contiguous United States (CONUS) for period 1979–2018. Using this examine meteorological land surface conditions associated recovery. These same then used classify based on precursor may represent predictable drivers event. We find can be diagnosed event inventory. Specifically, describe three drought: “dry demanding” events antecedent evaporative demand is high low, “evaporative” modest anomalies, but positive “stealth” droughts, different from other two anomalies relative classes. The exhibit somewhat geographic seasonal distributions. conclude indeed composite types analyses forecasts benefit approaches recognize existence phenomenological pathways.