Improving Future U.S. Drought Assessment

Since the beginning of the twenty-first century, the U.S. Southwest has been weathering the nation's first multidecadal megadrought, the most severe of many such droughts over the past 1,200 years. Droughts are becoming more frequent and longer-lasting, occurring against a backdrop of long-term regional drying trends in many areas. Associated impacts include a growing water crisis in the Southwest, groundwater declines across parts of the High Plains, increasing wildfire risk, and the growing occurrence of rapidly intensifying flash droughts. Together, these changing drought conditions are challenging the nation's resilience and ability to prepare for future drought risk. Conducted at the request of the National Oceanic and Atmospheric Administration (NOAA), with support from the Interstate Council on Water Policy, Improving Future U.S. Drought Assessment examines how drought assessment can better account for nonstationarity, or shifts in drought conditions and behaviors over time. The report explores how climate variability and change, along with evolving water and land management practices, are altering drought characteristics and affecting the usefulness of traditional assessment approaches that rely on historical baselines. The report proposes a framework for incorporating nonstationarity into drought assessment to support decision-making and future resilience. It outlines a two-pronged approach that addresses both short-term operational needs, such as drought monitoring and early warning, and long-term planning for water management, infrastructure, and adaptation. The report also highlights opportunities to strengthen drought indicators, impact data, and scientific understanding of drought dynamics to support more effective drought assessment across the United States.