A new University of Arizona study says "megadroughts" may be a recurring feature of the U.S. Southwestern region's climate.
The study to be published in the journal Geophysical Research Letters revealed a previously unknown multi-decade drought period in the second century for the region and suggests the area may have experienced more extended periods of aridity than originally believed.
University of Arizona geoscientists collected data for the study from the southern San Juan Mountains in south-central Colorado. The region serves as a primary drainage site for the Rio Grande and San Juan rivers.
Scientists say the prolonged drought in the 12th century and the newly discovered event in the second century may both have been influenced by warmer-than-average Northern Hemisphere temperatures.
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