Tree ring record of streamflow and drought in the upper Snake River



[1] Tree ring samples collected near the Snake River headwaters were augmented with preexisting tree ring chronologies to create a 415 year reconstruction of upper Snake River streamflow, extending the short instrumental record and providing the first description of multicentury water supply variability in this river. Results indicate that the region's early 21st century drought is severe even in the context of long-term climatic variability and that the instrumental record is representative of low-flow individual years. In terms of overall magnitude, droughts of the recent past are eclipsed by a sustained low-flow period lasting for over 30 years in the early to mid-1600s. A comparison of reconstructed Snake River flow with streamflow reconstructions of the Colorado, Sacramento, and Verde rivers suggests that changes in the predominance of zonal versus meridional atmospheric flow may have influenced drought patterns in the western United States through time.