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The unusual nature of recent snowpack declines in the North American cordillera

June 9, 2011

In western North America, snowpack has declined in recent decades, and further losses are projected through the 21st century. Here, we evaluate the uniqueness of recent declines using snowpackreconstructions from 66 tree-ring chronologies in key runoff-generating areas of the Colorado, Columbia, and Missouri River drainages. Over the past millennium, late 20th century snowpack reductions are almost unprecedented in magnitude across the northern Rocky Mountains and in their north-south synchrony acrossthe cordillera. Both the snowpack declines and their synchrony result from unparalleled springtime warming that is due to positive reinforcement of the anthropogenic warming by decadal variability. The increasing roleof warming on large-scale snowpack variability and trends foreshadows fundamental impacts on streamflow and water supplies across the western United States.

Publication Year 2011
Title The unusual nature of recent snowpack declines in the North American cordillera
DOI 10.1126/science.1201570
Authors Gregory T. Pederson, Stephen T. Gray, C.A. Woodhouse, Julio L. Betancourt, Daniel B. Fagre, Jeremy S. Littell, Emma Watson, B.H. Luckman, Lisa J. Graumlich
Publication Type Article
Publication Subtype Journal Article
Series Title Science
Index ID 70155831
Record Source USGS Publications Warehouse
USGS Organization Northern Rocky Mountain Science Center