Tree Rings Reveal Unmatched 2nd Century Drought in the Colorado River Basin

Subhrendu Gangopadhyay, Connie A. Woodhouse, Gregory J. McCabe, Cody C. Routson, David M. Meko

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


The ongoing 22-year drought in the Upper Colorado River Basin (UCRB) has been extremely severe, even in the context of the longest available tree-ring reconstruction of annual flow at Lees Ferry, Arizona, dating back to 762 CE. While many southwestern drought assessments have been limited to the past 1,200 years, longer paleorecords of moisture variability do exist for the UCRB. Here, gridded drought-atlas data in the UCRB domain along with naturalized streamflow data from the instrumental period (1906–2021) are used in a K-nearest neighbor nonparametric algorithm to develop a streamflow reconstruction for the Lees Ferry gage starting in 1 CE. The reconstruction reveals a second-century drought unmatched in severity by the current drought or by well-documented medieval period droughts in the UCRB. Although data are sparse, analysis of individual long tree-ring records and other paleoclimatic data also support the occurrence of an exceptional second-century drought.

Original languageEnglish (US)
Article numbere2022GL098781
JournalGeophysical Research Letters
Issue number11
StatePublished - Jun 16 2022


  • Colorado River
  • drought
  • streamflow
  • tree ring

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)


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