Paleoclimatic analogs to twentieth-century moisture regimes across the United States*

Decadal drought and wetness regimes similar to the three major moisture anomalies witnessed across the United States during the twentieth century are identified in continent-wide tree-ring reconstructions for the past 500 yr.

Decadal drought and wetness extremes punctuated the twentieth-century climate over the central and western United States. A strong pluvial in the early twentieth century covered a large portion of the West and lasted for more than a decade. Severe, sustained droughts afflicted most of the United States in the 1930s and 1950s (Fig. 1a). These moisture regimes have had an enormous impact on the economy and environment of the United States. The early …