Extensive Droughts in the Conterminous United States during Multiple Centuries

Abstract Extensive and severe droughts have substantial effects on water supplies, agriculture, aquatic ecosystems. To better understand these droughts, we used tree-ring-based reconstructions of the Palmer drought severity index (PDSI) for period 1475–2017 to examine that covered at least 33% conterminous United States (CONUS). We identified 37 spatially extensive events CONUS examined their spatial temporal patterns. The duration ranged from 3 12 yr average affected 43% CONUS. recent (2000–08) in southwestern CONUS, often referred as turn-of-the-century drought, is likely one longest during past 500 years. A principal components analysis PDSI data 1475 through 2017 resulted three (PCs) explain about 48% variability are helpful Analyses relations between PCs well-known climate indices, such indices El Niño–Southern Oscillation, indicate statistically significant correlations; however, correlations do not appear be large enough (all with an absolute value less than 0.45) useful development prediction models. Significance Statement U.S. time across space, a relative dryness/wetness 1475–2017. durations years States. Also, seven occurred after 1900. Because associations climatic conditions weak, use predictive models seems tenuous.