scholarly journals Significance of trends toward earlier snowmelt runoff, Columbia and Missouri Basin headwaters, western United States

2007 ◽  
Vol 34 (16) ◽  
Author(s):  
Johnnie N. Moore ◽  
Joel T. Harper ◽  
Mark C. Greenwood
2020 ◽  
Vol 6 (49) ◽  
pp. eaba5939
Author(s):  
Evan N. Dethier ◽  
Shannon L. Sartain ◽  
Carl E. Renshaw ◽  
Francis J. Magilligan

Complex hydroclimate in the United States and Canada has limited identification of possible ongoing changes in streamflow. We address this challenge by classifying 541 stations in the United States and Canada into 15 “hydro-regions,” each with similar seasonal streamflow characteristics. Analysis of seasonal streamflow records at these stations from 1910 to present indicates regionally coherent changes in the frequency of extreme high- and low-flow events. Where changes are significant, these events have, on average, doubled in frequency relative to 1950 to 1969. In hydro-regions influenced by snowmelt runoff, extreme high-flow event frequency has increased despite snowpack depletion by warming winter temperatures. In drought-prone hydro-regions of the western United States and Southeast, extreme low-flow event frequency has increased, particularly during summer and fall. The magnitude and regional consistency of these hydrologic changes warrant attention by watershed stakeholders. The hydro-region framework facilitates quantification and further analyses of these changes to extreme streamflow.


2005 ◽  
Vol 6 (4) ◽  
pp. 476-482 ◽  
Author(s):  
Gregory J. McCabe ◽  
Martyn P. Clark

Abstract The timing of snowmelt runoff (SMR) for 84 rivers in the western United States is examined to understand the character of SMR variability and the climate processes that may be driving changes in SMR timing. Results indicate that the timing of SMR for many rivers in the western United States has shifted to earlier in the snowmelt season. This shift occurred as a step change during the mid-1980s in conjunction with a step increase in spring and early-summer atmospheric pressures and temperatures over the western United States. The cause of the step change has not yet been determined.


Author(s):  
Jennifer J. Smith

Coherence of place often exists alongside irregularities in time in cycles, and chapter three turns to cycles linked by temporal markers. Ray Bradbury’s The Martian Chronicles (1950) follows a linear chronology and describes the exploration, conquest, and repopulation of Mars by humans. Conversely, Louise Erdrich’s Love Medicine (1984) jumps back and forth across time to narrate the lives of interconnected families in the western United States. Bradbury’s cycle invokes a confluence of historical forces—time as value-laden, work as a calling, and travel as necessitating standardized time—and contextualizes them in relation to anxieties about the space race. Erdrich’s cycle invokes broader, oppositional conceptions of time—as recursive and arbitrary and as causal and meaningful—to depict time as implicated in an entire system of measurement that made possible the destruction and exploitation of the Chippewa people. Both volumes understand the United States to be preoccupied with imperialist impulses. Even as they critique such projects, they also point to the tenacity with which individuals encounter these systems, and they do so by creating “interstitial temporalities,” which allow them to navigate time at the crossroads of language and culture.


NWSA Journal ◽  
2004 ◽  
Vol 16 (2) ◽  
pp. 180-189
Author(s):  
Karen L. Salley ◽  
Barbara Scott Winkler ◽  
Megan Celeen ◽  
Heidi Meck

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